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%{
/*
 * Parser for the Aic7xxx SCSI Host adapter sequencer assembler.
 *
 * Copyright (c) 1997, 1998, 2000 Justin T. Gibbs.
 * Copyright (c) 2001, 2002 Adaptec Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions, and the following disclaimer,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    substantially similar to the "NO WARRANTY" disclaimer below
 *    ("Disclaimer") and any redistribution must be conditioned upon
 *    including a substantially similar Disclaimer requirement for further
 *    binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 *
 * $Id: aicasm_gram.y,v 1.1.1.1 2004-04-15 02:16:35 phoenix Exp $
 *
 * $FreeBSD$
 */

#include <sys/types.h>

#include <inttypes.h>
#include <regex.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>

#ifdef __linux__
#include "../queue.h"
#else
#include <sys/queue.h>
#endif

#include "aicasm.h"
#include "aicasm_symbol.h"
#include "aicasm_insformat.h"

int yylineno;
char *yyfilename;
char stock_prefix[] = "aic_";
char *prefix = stock_prefix;
char *patch_arg_list;
char *versions;
static char errbuf[255];
static char regex_pattern[255];
static symbol_t *cur_symbol;
static symbol_t *field_symbol;
static symbol_t *scb_or_sram_symbol;
static symtype cur_symtype;
static symbol_ref_t accumulator;
static symbol_ref_t mode_ptr;
static symbol_ref_t allones;
static symbol_ref_t allzeros;
static symbol_ref_t none;
static symbol_ref_t sindex;
static int instruction_ptr;
static int num_srams;
static int sram_or_scb_offset;
static int download_constant_count;
static int in_critical_section;
static u_int enum_increment;
static u_int enum_next_value;

static void process_field(int field_type, symbol_t *sym, int mask);
static void initialize_symbol(symbol_t *symbol);
static void add_macro_arg(const char *argtext, int position);
static void add_macro_body(const char *bodytext);
static void process_register(symbol_t **p_symbol);
static void format_1_instr(int opcode, symbol_ref_t *dest,
                           expression_t *immed, symbol_ref_t *src, int ret);
static void format_2_instr(int opcode, symbol_ref_t *dest,
                           expression_t *places, symbol_ref_t *src, int ret);
static void format_3_instr(int opcode, symbol_ref_t *src,
                           expression_t *immed, symbol_ref_t *address);
static void test_readable_symbol(symbol_t *symbol);
static void test_writable_symbol(symbol_t *symbol);
static void type_check(symbol_t *symbol, expression_t *expression, int and_op);
static void make_expression(expression_t *immed, int value);
static void add_conditional(symbol_t *symbol);
static void add_version(const char *verstring);
static int  is_download_const(expression_t *immed);

#define SRAM_SYMNAME "SRAM_BASE"
#define SCB_SYMNAME "SCB_BASE"
%}

%union {
        u_int           value;
        char            *str;
        symbol_t        *sym;
        symbol_ref_t    sym_ref;
        expression_t    expression;
}

%token T_REGISTER

%token <value> T_CONST

%token T_EXPORT

%token T_DOWNLOAD

%token T_SCB

%token T_SRAM

%token T_ALIAS

%token T_SIZE

%token T_EXPR_LSHIFT

%token T_EXPR_RSHIFT

%token <value> T_ADDRESS

%token T_ACCESS_MODE

%token T_MODES

%token T_DEFINE

%token T_SET_SRC_MODE

%token T_SET_DST_MODE

%token <value> T_MODE

%token T_BEGIN_CS

%token T_END_CS

%token T_FIELD

%token T_ENUM

%token T_MASK

%token <value> T_NUMBER

%token <str> T_PATH T_STRING T_ARG T_MACROBODY

%token <sym> T_CEXPR

%token T_EOF T_INCLUDE T_VERSION T_PREFIX T_PATCH_ARG_LIST

%token <value> T_SHR T_SHL T_ROR T_ROL

%token <value> T_MVI T_MOV T_CLR T_BMOV

%token <value> T_JMP T_JC T_JNC T_JE T_JNE T_JNZ T_JZ T_CALL

%token <value> T_ADD T_ADC

%token <value> T_INC T_DEC

%token <value> T_STC T_CLC

%token <value> T_CMP T_NOT T_XOR

%token <value> T_TEST T_AND

%token <value> T_OR

%token T_RET

%token T_NOP

%token T_ACCUM T_ALLONES T_ALLZEROS T_NONE T_SINDEX T_MODE_PTR

%token T_A

%token <sym> T_SYMBOL

%token T_NL

%token T_IF T_ELSE T_ELSE_IF T_ENDIF

%type <sym_ref> reg_symbol address destination source opt_source

%type <expression> expression immediate immediate_or_a

%type <value> export ret f1_opcode f2_opcode jmp_jc_jnc_call jz_jnz je_jne

%type <value> mode_value mode_list macro_arglist

%left '|'
%left '&'
%left T_EXPR_LSHIFT T_EXPR_RSHIFT
%left '+' '-'
%left '*' '/'
%right '~'
%nonassoc UMINUS
%%

program:
        include
|       program include
|       prefix
|       program prefix
|       patch_arg_list
|       program patch_arg_list
|       version
|       program version
|       register
|       program register
|       constant
|       program constant
|       macrodefn
|       program macrodefn
|       scratch_ram
|       program scratch_ram
|       scb
|       program scb
|       label
|       program label
|       set_src_mode
|       program set_src_mode
|       set_dst_mode
|       program set_dst_mode
|       critical_section_start
|       program critical_section_start
|       critical_section_end
|       program critical_section_end
|       conditional
|       program conditional
|       code
|       program code
;

include:
        T_INCLUDE '<' T_PATH '>'
        {
                include_file($3, BRACKETED_INCLUDE);
        }
|       T_INCLUDE '"' T_PATH '"'
        {
                include_file($3, QUOTED_INCLUDE);
        }
;

prefix:
        T_PREFIX '=' T_STRING
        {
                if (prefix != stock_prefix)
                        stop("Prefix multiply defined",
                             EX_DATAERR);
                prefix = strdup($3);
                if (prefix == NULL)
                        stop("Unable to record prefix", EX_SOFTWARE);
        }
;

patch_arg_list:
        T_PATCH_ARG_LIST '=' T_STRING
        {
                if (patch_arg_list != NULL)
                        stop("Patch argument list multiply defined",
                             EX_DATAERR);
                patch_arg_list = strdup($3);
                if (patch_arg_list == NULL)
                        stop("Unable to record patch arg list", EX_SOFTWARE);
        }
;

version:
        T_VERSION '=' T_STRING
        { add_version($3); }
;

register:
        T_REGISTER { cur_symtype = REGISTER; } reg_definition
;

reg_definition:
        T_SYMBOL '{'
                {
                        if ($1->type != UNINITIALIZED) {
                                stop("Register multiply defined", EX_DATAERR);
                                /* NOTREACHED */
                        }
                        cur_symbol = $1; 
                        cur_symbol->type = cur_symtype;
                        initialize_symbol(cur_symbol);
                }
                reg_attribute_list
        '}'
                {                    
                        /*
                         * Default to allowing everything in for registers
                         * with no bit or mask definitions.
                         */
                        if (cur_symbol->info.rinfo->valid_bitmask == 0)
                                cur_symbol->info.rinfo->valid_bitmask = 0xFF;

                        if (cur_symbol->info.rinfo->size == 0)
                                cur_symbol->info.rinfo->size = 1;

                        /*
                         * This might be useful for registers too.
                         */
                        if (cur_symbol->type != REGISTER) {
                                if (cur_symbol->info.rinfo->address == 0)
                                        cur_symbol->info.rinfo->address =
                                            sram_or_scb_offset;
                                sram_or_scb_offset +=
                                    cur_symbol->info.rinfo->size;
                        }
                        cur_symbol = NULL;
                }
;

reg_attribute_list:
        reg_attribute
|       reg_attribute_list reg_attribute
;

reg_attribute:          
        reg_address
|       size
|       access_mode
|       modes
|       field_defn
|       enum_defn
|       mask_defn
|       alias
|       accumulator
|       mode_pointer
|       allones
|       allzeros
|       none
|       sindex
;

reg_address:
        T_ADDRESS T_NUMBER
        {
                cur_symbol->info.rinfo->address = $2;
        }
;

size:
        T_SIZE T_NUMBER
        {
                cur_symbol->info.rinfo->size = $2;
                if (scb_or_sram_symbol != NULL) {
                        u_int max_addr;
                        u_int sym_max_addr;

                        max_addr = scb_or_sram_symbol->info.rinfo->address
                                 + scb_or_sram_symbol->info.rinfo->size;
                        sym_max_addr = cur_symbol->info.rinfo->address
                                     + cur_symbol->info.rinfo->size;

                        if (sym_max_addr > max_addr)
                                stop("SCB or SRAM space exhausted", EX_DATAERR);
                }
        }
;

access_mode:
        T_ACCESS_MODE T_MODE
        {
                cur_symbol->info.rinfo->mode = $2;
        }
;

modes:
        T_MODES mode_list
        {
                cur_symbol->info.rinfo->modes = $2;
        }
;

mode_list:
        mode_value
        {
                $$ = $1;
        }
|       mode_list ',' mode_value
        {
                $$ = $1 | $3;
        }
;

mode_value:
        T_NUMBER
        {
                if ($1 > 4) {
                        stop("Valid register modes range between 0 and 4.",
                             EX_DATAERR);
                        /* NOTREACHED */
                }

                $$ = (0x1 << $1);
        }
|       T_SYMBOL
        {
                symbol_t *symbol;

                symbol = $1;
                if (symbol->type != CONST) {
                        stop("Only \"const\" symbols allowed in "
                             "mode definitions.", EX_DATAERR);
                        /* NOTREACHED */
                }
                if (symbol->info.cinfo->value > 4) {
                        stop("Valid register modes range between 0 and 4.",
                             EX_DATAERR);
                        /* NOTREACHED */
                }
                $$ = (0x1 << symbol->info.cinfo->value);
        }
;

field_defn:
        T_FIELD
                {
                        field_symbol = NULL;
                        enum_next_value = 0;
                        enum_increment = 1;
                }
        '{' enum_entry_list '}'
|       T_FIELD T_SYMBOL expression
                {
                        process_field(FIELD, $2, $3.value);
                        field_symbol = $2;
                        enum_next_value = 0;
                        enum_increment = 0x01 << (ffs($3.value) - 1);
                }
        '{' enum_entry_list '}'
|       T_FIELD T_SYMBOL expression
        {
                process_field(FIELD, $2, $3.value);
        }
;

enum_defn:
        T_ENUM
                {
                        field_symbol = NULL;
                        enum_next_value = 0;
                        enum_increment = 1;
                }
        '{' enum_entry_list '}'
|       T_ENUM T_SYMBOL expression
                {
                        process_field(ENUM, $2, $3.value);
                        field_symbol = $2;
                        enum_next_value = 0;
                        enum_increment = 0x01 << (ffs($3.value) - 1);
                }
        '{' enum_entry_list '}'
;

enum_entry_list:
        enum_entry
|       enum_entry_list ',' enum_entry
;

enum_entry:
        T_SYMBOL
        {
                process_field(ENUM_ENTRY, $1, enum_next_value);
                enum_next_value += enum_increment;
        }
|       T_SYMBOL expression
        {
                process_field(ENUM_ENTRY, $1, $2.value);
                enum_next_value = $2.value + enum_increment;
        }
;

mask_defn:
        T_MASK T_SYMBOL expression
        {
                process_field(MASK, $2, $3.value);
        }
;

alias:
        T_ALIAS T_SYMBOL
        {
                if ($2->type != UNINITIALIZED) {
                        stop("Re-definition of register alias",
                             EX_DATAERR);
                        /* NOTREACHED */
                }
                $2->type = ALIAS;
                initialize_symbol($2);
                $2->info.ainfo->parent = cur_symbol;
        }
;

accumulator:
        T_ACCUM
        {
                if (accumulator.symbol != NULL) {
                        stop("Only one accumulator definition allowed",
                             EX_DATAERR);
                        /* NOTREACHED */
                }
                accumulator.symbol = cur_symbol;
        }
;

mode_pointer:
        T_MODE_PTR
        {
                if (mode_ptr.symbol != NULL) {
                        stop("Only one mode pointer definition allowed",
                             EX_DATAERR);
                        /* NOTREACHED */
                }
                mode_ptr.symbol = cur_symbol;
        }
;

allones:
        T_ALLONES
        {
                if (allones.symbol != NULL) {
                        stop("Only one definition of allones allowed",
                             EX_DATAERR);
                        /* NOTREACHED */
                }
                allones.symbol = cur_symbol;
        }
;

allzeros:
        T_ALLZEROS
        {
                if (allzeros.symbol != NULL) {
                        stop("Only one definition of allzeros allowed",
                             EX_DATAERR);
                        /* NOTREACHED */
                }
                allzeros.symbol = cur_symbol;
        }
;

none:
        T_NONE
        {
                if (none.symbol != NULL) {
                        stop("Only one definition of none allowed",
                             EX_DATAERR);
                        /* NOTREACHED */
                }
                none.symbol = cur_symbol;
        }
;

sindex:
        T_SINDEX
        {
                if (sindex.symbol != NULL) {
                        stop("Only one definition of sindex allowed",
                             EX_DATAERR);
                        /* NOTREACHED */
                }
                sindex.symbol = cur_symbol;
        }
;

expression:
        expression '|' expression
        {
                 $$.value = $1.value | $3.value;
                 symlist_merge(&$$.referenced_syms,
                               &$1.referenced_syms,
                               &$3.referenced_syms);
        }
|       expression '&' expression
        {
                $$.value = $1.value & $3.value;
                symlist_merge(&$$.referenced_syms,
                               &$1.referenced_syms,
                               &$3.referenced_syms);
        }
|       expression '+' expression
        {
                $$.value = $1.value + $3.value;
                symlist_merge(&$$.referenced_syms,
                               &$1.referenced_syms,
                               &$3.referenced_syms);
        }
|       expression '-' expression
        {
                $$.value = $1.value - $3.value;
                symlist_merge(&($$.referenced_syms),
                               &($1.referenced_syms),
                               &($3.referenced_syms));
        }
|       expression '*' expression
        {
                $$.value = $1.value * $3.value;
                symlist_merge(&($$.referenced_syms),
                               &($1.referenced_syms),
                               &($3.referenced_syms));
        }
|       expression '/' expression
        {
                $$.value = $1.value / $3.value;
                symlist_merge(&($$.referenced_syms),
                               &($1.referenced_syms),
                               &($3.referenced_syms));
        }
|       expression T_EXPR_LSHIFT expression
        {
                $$.value = $1.value << $3.value;
                symlist_merge(&$$.referenced_syms,
                               &$1.referenced_syms,
                               &$3.referenced_syms);
        }
|       expression T_EXPR_RSHIFT expression
        {
                $$.value = $1.value >> $3.value;
                symlist_merge(&$$.referenced_syms,
                               &$1.referenced_syms,
                               &$3.referenced_syms);
        }
|       '(' expression ')'
        {
                $$ = $2;
        }
|       '~' expression
        {
                $$ = $2;
                $$.value = (~$$.value) & 0xFF;
        }
|       '-' expression %prec UMINUS
        {
                $$ = $2;
                $$.value = -$$.value;
        }
|       T_NUMBER
        {
                $$.value = $1;
                SLIST_INIT(&$$.referenced_syms);
        }
|       T_SYMBOL
        {
                symbol_t *symbol;

                symbol = $1;
                switch (symbol->type) {
                case ALIAS:
                        symbol = $1->info.ainfo->parent;
                case REGISTER:
                case SCBLOC:
                case SRAMLOC:
                        $$.value = symbol->info.rinfo->address;
                        break;
                case MASK:
                case FIELD:
                case ENUM:
                case ENUM_ENTRY:
                        $$.value = symbol->info.finfo->value;
                        break;
                case DOWNLOAD_CONST:
                case CONST:
                        $$.value = symbol->info.cinfo->value;
                        break;
                case UNINITIALIZED:
                default:
                {
                        snprintf(errbuf, sizeof(errbuf),
                                 "Undefined symbol %s referenced",
                                 symbol->name);
                        stop(errbuf, EX_DATAERR);
                        /* NOTREACHED */
                        break;
                }
                }
                SLIST_INIT(&$$.referenced_syms);
                symlist_add(&$$.referenced_syms, symbol, SYMLIST_INSERT_HEAD);
        }
;

constant:
        T_CONST T_SYMBOL expression 
        {
                if ($2->type != UNINITIALIZED) {
                        stop("Re-definition of symbol as a constant",
                             EX_DATAERR);
                        /* NOTREACHED */
                }
                $2->type = CONST;
                initialize_symbol($2);
                $2->info.cinfo->value = $3.value;
        }
|       T_CONST T_SYMBOL T_DOWNLOAD
        {
                if ($1) {
                        stop("Invalid downloaded constant declaration",
                             EX_DATAERR);
                        /* NOTREACHED */
                }
                if ($2->type != UNINITIALIZED) {
                        stop("Re-definition of symbol as a downloaded constant",
                             EX_DATAERR);
                        /* NOTREACHED */
                }
                $2->type = DOWNLOAD_CONST;
                initialize_symbol($2);
                $2->info.cinfo->value = download_constant_count++;
        }
;

macrodefn_prologue:
        T_DEFINE T_SYMBOL
        {
                if ($2->type != UNINITIALIZED) {
                        stop("Re-definition of symbol as a macro",
                             EX_DATAERR);
                        /* NOTREACHED */
                }
                cur_symbol = $2;
                cur_symbol->type = MACRO;
                initialize_symbol(cur_symbol);
        }
;

macrodefn:
        macrodefn_prologue T_MACROBODY
        {
                add_macro_body($2);
        }
|       macrodefn_prologue '(' macro_arglist ')' T_MACROBODY
        {
                add_macro_body($5);
                cur_symbol->info.macroinfo->narg = $3;
        }
;

macro_arglist:
        {
                /* Macros can take no arguments */
                $$ = 0;
        }
|       T_ARG
        {
                $$ = 1;
                add_macro_arg($1, 0);
        }
|       macro_arglist ',' T_ARG
        {
                if ($1 == 0) {
                        stop("Comma without preceeding argument in arg list",
                             EX_DATAERR);
                        /* NOTREACHED */
                }
                $$ = $1 + 1;
                add_macro_arg($3, $1);
        }
;

scratch_ram:
        T_SRAM '{'
                {
                        snprintf(errbuf, sizeof(errbuf), "%s%d", SRAM_SYMNAME,
                                 num_srams);
                        cur_symbol = symtable_get(SRAM_SYMNAME);
                        cur_symtype = SRAMLOC;
                        cur_symbol->type = SRAMLOC;
                        initialize_symbol(cur_symbol);
                }
                reg_address
                {
                        sram_or_scb_offset = cur_symbol->info.rinfo->address;
                }
                size
                {
                        scb_or_sram_symbol = cur_symbol;
                }
                scb_or_sram_attributes
        '}'
                {
                        cur_symbol = NULL;
                        scb_or_sram_symbol = NULL;
                }
;

scb:
        T_SCB '{'
                {
                        cur_symbol = symtable_get(SCB_SYMNAME);
                        cur_symtype = SCBLOC;
                        if (cur_symbol->type != UNINITIALIZED) {
                                stop("Only one SRAM definition allowed",
                                     EX_SOFTWARE);
                                /* NOTREACHED */
                        }
                        cur_symbol->type = SCBLOC;
                        initialize_symbol(cur_symbol);
                        /* 64 bytes of SCB space */
                        cur_symbol->info.rinfo->size = 64;
                }
                reg_address
                {
                        sram_or_scb_offset = cur_symbol->info.rinfo->address;
                }
                size
                {
                        scb_or_sram_symbol = cur_symbol;
                }
                scb_or_sram_attributes
        '}'
                {
                        cur_symbol = NULL;
                        scb_or_sram_symbol = NULL;
                }
;

scb_or_sram_attributes:
        /* NULL definition is okay */
|       modes
|       scb_or_sram_reg_list
|       modes scb_or_sram_reg_list
;

scb_or_sram_reg_list:
        reg_definition
|       scb_or_sram_reg_list reg_definition
;

reg_symbol:
        T_SYMBOL
        {
                process_register(&$1);
                $$.symbol = $1;
                $$.offset = 0;
        }
|       T_SYMBOL '[' T_SYMBOL ']'
        {
                process_register(&$1);
                if ($3->type != CONST) {
                        stop("register offset must be a constant", EX_DATAERR);
                        /* NOTREACHED */
                }
                if (($3->info.cinfo->value + 1) > $1->info.rinfo->size) {
                        stop("Accessing offset beyond range of register",
                             EX_DATAERR);
                        /* NOTREACHED */
                }
                $$.symbol = $1;
                $$.offset = $3->info.cinfo->value;
        }
|       T_SYMBOL '[' T_NUMBER ']'
        {
                process_register(&$1);
                if (($3 + 1) > $1->info.rinfo->size) {
                        stop("Accessing offset beyond range of register",
                             EX_DATAERR);
                        /* NOTREACHED */
                }
                $$.symbol = $1;
                $$.offset = $3;
        }
|       T_A
        {
                if (accumulator.symbol == NULL) {
                        stop("No accumulator has been defined", EX_DATAERR);
                        /* NOTREACHED */
                }
                $$.symbol = accumulator.symbol;
                $$.offset = 0;
        }
;

destination:
        reg_symbol
        {
                test_writable_symbol($1.symbol);
                $$ = $1;
        }
;

immediate:
        expression
        { $$ = $1; }
;

immediate_or_a:
        expression
        {
                if ($1.value == 0 && is_download_const(&$1) == 0) {
                        snprintf(errbuf, sizeof(errbuf),
                                 "\nExpression evaluates to 0 and thus "
                                 "references the accumulator.\n "
                                 "If this is the desired effect, use 'A' "
                                 "instead.\n");
                        stop(errbuf, EX_DATAERR);
                }
                $$ = $1;
        }
|       T_A
        {
                SLIST_INIT(&$$.referenced_syms);
                symlist_add(&$$.referenced_syms, accumulator.symbol,
                            SYMLIST_INSERT_HEAD);
                $$.value = 0;
        }
;

source:
        reg_symbol
        {
                test_readable_symbol($1.symbol);
                $$ = $1;
        }
;

opt_source:
        {
                $$.symbol = NULL;
                $$.offset = 0;
        }
|       ',' source
        { $$ = $2; }
;

ret:
        { $$ = 0; }
|       T_RET
        { $$ = 1; }
;

set_src_mode:
        T_SET_SRC_MODE T_NUMBER ';'
        {
                src_mode = $2;
        }
;

set_dst_mode:
        T_SET_DST_MODE T_NUMBER ';'
        {
                dst_mode = $2;
        }
;

critical_section_start:
        T_BEGIN_CS ';'
        {
                critical_section_t *cs;

                if (in_critical_section != FALSE) {
                        stop("Critical Section within Critical Section",
                             EX_DATAERR);
                        /* NOTREACHED */
                }
                cs = cs_alloc();
                cs->begin_addr = instruction_ptr;
                in_critical_section = TRUE;
        }
;

critical_section_end:
        T_END_CS ';'
        {
                critical_section_t *cs;

                if (in_critical_section == FALSE) {
                        stop("Unballanced 'end_cs'", EX_DATAERR);
                        /* NOTREACHED */
                }
                cs = TAILQ_LAST(&cs_tailq, cs_tailq);
                cs->end_addr = instruction_ptr;
                in_critical_section = FALSE;
        }
;

export:
        { $$ = 0; }
|       T_EXPORT
        { $$ = 1; }
;

label:
        export T_SYMBOL ':'
        {
                if ($2->type != UNINITIALIZED) {
                        stop("Program label multiply defined", EX_DATAERR);
                        /* NOTREACHED */
                }
                $2->type = LABEL;
                initialize_symbol($2);
                $2->info.linfo->address = instruction_ptr;
                $2->info.linfo->exported = $1;
        }
;

address:
        T_SYMBOL
        {
                $$.symbol = $1;
                $$.offset = 0;
        }
|       T_SYMBOL '+' T_NUMBER
        {
                $$.symbol = $1;
                $$.offset = $3;
        }
|       T_SYMBOL '-' T_NUMBER
        {
                $$.symbol = $1;
                $$.offset = -$3;
        }
|       '.'
        {
                $$.symbol = NULL;
                $$.offset = 0;
        }
|       '.' '+' T_NUMBER
        {
                $$.symbol = NULL;
                $$.offset = $3;
        }
|       '.' '-' T_NUMBER
        {
                $$.symbol = NULL;
                $$.offset = -$3;
        }
;

conditional:
        T_IF T_CEXPR '{'
        {
                scope_t *new_scope;

                add_conditional($2);
                new_scope = scope_alloc();
                new_scope->type = SCOPE_IF;
                new_scope->begin_addr = instruction_ptr;
                new_scope->func_num = $2->info.condinfo->func_num;
        }
|       T_ELSE T_IF T_CEXPR '{'
        {
                scope_t *new_scope;
                scope_t *scope_context;
                scope_t *last_scope;

                /*
                 * Ensure that the previous scope is either an
                 * if or and else if.
                 */
                scope_context = SLIST_FIRST(&scope_stack);
                last_scope = TAILQ_LAST(&scope_context->inner_scope,
                                        scope_tailq);
                if (last_scope == NULL
                 || last_scope->type == T_ELSE) {

                        stop("'else if' without leading 'if'", EX_DATAERR);
                        /* NOTREACHED */
                }
                add_conditional($3);
                new_scope = scope_alloc();
                new_scope->type = SCOPE_ELSE_IF;
                new_scope->begin_addr = instruction_ptr;
                new_scope->func_num = $3->info.condinfo->func_num;
        }
|       T_ELSE '{'
        {
                scope_t *new_scope;
                scope_t *scope_context;
                scope_t *last_scope;

                /*
                 * Ensure that the previous scope is either an
                 * if or and else if.
                 */
                scope_context = SLIST_FIRST(&scope_stack);
                last_scope = TAILQ_LAST(&scope_context->inner_scope,
                                        scope_tailq);
                if (last_scope == NULL
                 || last_scope->type == SCOPE_ELSE) {

                        stop("'else' without leading 'if'", EX_DATAERR);
                        /* NOTREACHED */
                }
                new_scope = scope_alloc();
                new_scope->type = SCOPE_ELSE;
                new_scope->begin_addr = instruction_ptr;
        }
;

conditional:
        '}'
        {
                scope_t *scope_context;

                scope_context = SLIST_FIRST(&scope_stack);
                if (scope_context->type == SCOPE_ROOT) {
                        stop("Unexpected '}' encountered", EX_DATAERR);
                        /* NOTREACHED */
                }

                scope_context->end_addr = instruction_ptr;

                /* Pop the scope */
                SLIST_REMOVE_HEAD(&scope_stack, scope_stack_links);

                process_scope(scope_context);

                if (SLIST_FIRST(&scope_stack) == NULL) {
                        stop("Unexpected '}' encountered", EX_DATAERR);
                        /* NOTREACHED */
                }
        }
;

f1_opcode:
        T_AND { $$ = AIC_OP_AND; }
|       T_XOR { $$ = AIC_OP_XOR; }
|       T_ADD { $$ = AIC_OP_ADD; }
|       T_ADC { $$ = AIC_OP_ADC; }
;

code:
        f1_opcode destination ',' immediate_or_a opt_source ret ';'
        {
                format_1_instr($1, &$2, &$4, &$5, $6);
        }
;

code:
        T_OR reg_symbol ',' immediate_or_a opt_source ret ';'
        {
                format_1_instr(AIC_OP_OR, &$2, &$4, &$5, $6);
        }
;

code:
        T_INC destination opt_source ret ';'
        {
                expression_t immed;

                make_expression(&immed, 1);
                format_1_instr(AIC_OP_ADD, &$2, &immed, &$3, $4);
        }
;

code:
        T_DEC destination opt_source ret ';'
        {
                expression_t immed;

                make_expression(&immed, -1);
                format_1_instr(AIC_OP_ADD, &$2, &immed, &$3, $4);
        }
;

code:
        T_CLC ret ';'
        {
                expression_t immed;

                make_expression(&immed, -1);
                format_1_instr(AIC_OP_ADD, &none, &immed, &allzeros, $2);
        }
|       T_CLC T_MVI destination ',' immediate_or_a ret ';'
        {
                format_1_instr(AIC_OP_ADD, &$3, &$5, &allzeros, $6);
        }
;

code:
        T_STC ret ';'
        {
                expression_t immed;

                make_expression(&immed, 1);
                format_1_instr(AIC_OP_ADD, &none, &immed, &allones, $2);
        }
|       T_STC destination ret ';'
        {
                expression_t immed;

                make_expression(&immed, 1);
                format_1_instr(AIC_OP_ADD, &$2, &immed, &allones, $3);
        }
;

code:
        T_BMOV destination ',' source ',' immediate ret ';'
        {
                format_1_instr(AIC_OP_BMOV, &$2, &$6, &$4, $7);
        }
;

code:
        T_MOV destination ',' source ret ';'
        {
                expression_t immed;

                make_expression(&immed, 1);
                format_1_instr(AIC_OP_BMOV, &$2, &immed, &$4, $5);
        }
;

code:
        T_MVI destination ',' immediate ret ';'
        {
                if ($4.value == 0
                 && is_download_const(&$4) == 0) {
                        expression_t immed;

                        /*
                         * Allow move immediates of 0 so that macros,
                         * that can't know the immediate's value and
                         * otherwise compensate, still work.
                         */
                        make_expression(&immed, 1);
                        format_1_instr(AIC_OP_BMOV, &$2, &immed, &allzeros, $5);
                } else {
                        format_1_instr(AIC_OP_OR, &$2, &$4, &allzeros, $5);
                }
        }
;

code:
        T_NOT destination opt_source ret ';'
        {
                expression_t immed;

                make_expression(&immed, 0xff);
                format_1_instr(AIC_OP_XOR, &$2, &immed, &$3, $4);
        }
;

code:
        T_CLR destination ret ';'
        {
                expression_t immed;

                make_expression(&immed, 0xff);
                format_1_instr(AIC_OP_AND, &$2, &immed, &allzeros, $3);
        }
;

code:
        T_NOP ret ';'
        {
                expression_t immed;

                make_expression(&immed, 0xff);
                format_1_instr(AIC_OP_AND, &none, &immed, &allzeros, $2);
        }
;

code:
        T_RET ';'
        {
                expression_t immed;

                make_expression(&immed, 0xff);
                format_1_instr(AIC_OP_AND, &none, &immed, &allzeros, TRUE);
        }
;

        /*
         * This grammer differs from the one in the aic7xxx
         * reference manual since the grammer listed there is
         * ambiguous and causes a shift/reduce conflict.
         * It also seems more logical as the "immediate"
         * argument is listed as the second arg like the
         * other formats.
         */

f2_opcode:
        T_SHL { $$ = AIC_OP_SHL; }
|       T_SHR { $$ = AIC_OP_SHR; }
|       T_ROL { $$ = AIC_OP_ROL; }
|       T_ROR { $$ = AIC_OP_ROR; }
;

code:
        f2_opcode destination ',' expression opt_source ret ';'
        {
                format_2_instr($1, &$2, &$4, &$5, $6);
        }
;

jmp_jc_jnc_call:
        T_JMP   { $$ = AIC_OP_JMP; }
|       T_JC    { $$ = AIC_OP_JC; }
|       T_JNC   { $$ = AIC_OP_JNC; }
|       T_CALL  { $$ = AIC_OP_CALL; }
;

jz_jnz:
        T_JZ    { $$ = AIC_OP_JZ; }
|       T_JNZ   { $$ = AIC_OP_JNZ; }
;

je_jne:
        T_JE    { $$ = AIC_OP_JE; }
|       T_JNE   { $$ = AIC_OP_JNE; }
;

code:
        jmp_jc_jnc_call address ';'
        {
                expression_t immed;

                make_expression(&immed, 0);
                format_3_instr($1, &sindex, &immed, &$2);
        }
;

code:
        T_OR reg_symbol ',' immediate jmp_jc_jnc_call address ';'
        {
                format_3_instr($5, &$2, &$4, &$6);
        }
;

code:
        T_TEST source ',' immediate_or_a jz_jnz address ';'
        {
                format_3_instr($5, &$2, &$4, &$6);
        }
;

code:
        T_CMP source ',' immediate_or_a je_jne address ';'
        {
                format_3_instr($5, &$2, &$4, &$6);
        }
;

code:
        T_MOV source jmp_jc_jnc_call address ';'
        {
                expression_t immed;

                make_expression(&immed, 0);
                format_3_instr($3, &$2, &immed, &$4);
        }
;

code:
        T_MVI immediate jmp_jc_jnc_call address ';'
        {
                format_3_instr($3, &allzeros, &$2, &$4);
        }
;

%%

static void
process_field(int field_type, symbol_t *sym, int value)
{
        /*
         * Add the current register to its
         * symbol list, if it already exists,
         * warn if we are setting it to a
         * different value, or in the bit to
         * the "allowed bits" of this register.
         */
        if (sym->type == UNINITIALIZED) {
                sym->type = field_type;
                initialize_symbol(sym);
                sym->info.finfo->value = value;
                if (field_type != ENUM_ENTRY) {
                        if (field_type != MASK && value == 0) {
                                stop("Empty Field, or Enum", EX_DATAERR);
                                /* NOTREACHED */
                        }
                        sym->info.finfo->value = value;
                        sym->info.finfo->mask = value;
                } else if (field_symbol != NULL) {
                        sym->info.finfo->mask = field_symbol->info.finfo->value;
                } else {
                        sym->info.finfo->mask = 0xFF;
                }
        } else if (sym->type != field_type) {
                stop("Field definition mirrors a definition of the same "
                     " name, but a different type", EX_DATAERR);
                /* NOTREACHED */
        } else if (value != sym->info.finfo->value) {
                stop("Field redefined with a conflicting value", EX_DATAERR);
                /* NOTREACHED */
        }
        /* Fail if this symbol is already listed */
        if (symlist_search(&(sym->info.finfo->symrefs),
                           cur_symbol->name) != NULL) {
                stop("Field defined multiple times for register", EX_DATAERR);
                /* NOTREACHED */
        }
        symlist_add(&(sym->info.finfo->symrefs), cur_symbol,
                    SYMLIST_INSERT_HEAD);
        cur_symbol->info.rinfo->valid_bitmask |= sym->info.finfo->mask;
        cur_symbol->info.rinfo->typecheck_masks = TRUE;
        symlist_add(&(cur_symbol->info.rinfo->fields), sym, SYMLIST_SORT);
}

static void
initialize_symbol(symbol_t *symbol)
{
        switch (symbol->type) {
        case UNINITIALIZED:
                stop("Call to initialize_symbol with type field unset",
                     EX_SOFTWARE);
                /* NOTREACHED */
                break;
        case REGISTER:
        case SRAMLOC:
        case SCBLOC:
                symbol->info.rinfo =
                    (struct reg_info *)malloc(sizeof(struct reg_info));
                if (symbol->info.rinfo == NULL) {
                        stop("Can't create register info", EX_SOFTWARE);
                        /* NOTREACHED */
                }
                memset(symbol->info.rinfo, 0,
                       sizeof(struct reg_info));
                SLIST_INIT(&(symbol->info.rinfo->fields));
                /*
                 * Default to allowing access in all register modes
                 * or to the mode specified by the SCB or SRAM space
                 * we are in.
                 */
                if (scb_or_sram_symbol != NULL)
                        symbol->info.rinfo->modes =
                            scb_or_sram_symbol->info.rinfo->modes;
                else
                        symbol->info.rinfo->modes = ~0;
                break;
        case ALIAS:
                symbol->info.ainfo =
                    (struct alias_info *)malloc(sizeof(struct alias_info));
                if (symbol->info.ainfo == NULL) {
                        stop("Can't create alias info", EX_SOFTWARE);
                        /* NOTREACHED */
                }
                memset(symbol->info.ainfo, 0,
                       sizeof(struct alias_info));
                break;
        case MASK:
        case FIELD:
        case ENUM:
        case ENUM_ENTRY:
                symbol->info.finfo =
                    (struct field_info *)malloc(sizeof(struct field_info));
                if (symbol->info.finfo == NULL) {
                        stop("Can't create field info", EX_SOFTWARE);
                        /* NOTREACHED */
                }
                memset(symbol->info.finfo, 0, sizeof(struct field_info));
                SLIST_INIT(&(symbol->info.finfo->symrefs));
                break;
        case CONST:
        case DOWNLOAD_CONST:
                symbol->info.cinfo =
                    (struct const_info *)malloc(sizeof(struct const_info));
                if (symbol->info.cinfo == NULL) {
                        stop("Can't create alias info", EX_SOFTWARE);
                        /* NOTREACHED */
                }
                memset(symbol->info.cinfo, 0,
                       sizeof(struct const_info));
                break;
        case LABEL:
                symbol->info.linfo =
                    (struct label_info *)malloc(sizeof(struct label_info));
                if (symbol->info.linfo == NULL) {
                        stop("Can't create label info", EX_SOFTWARE);
                        /* NOTREACHED */
                }
                memset(symbol->info.linfo, 0,
                       sizeof(struct label_info));
                break;
        case CONDITIONAL:
                symbol->info.condinfo =
                    (struct cond_info *)malloc(sizeof(struct cond_info));
                if (symbol->info.condinfo == NULL) {
                        stop("Can't create conditional info", EX_SOFTWARE);
                        /* NOTREACHED */
                }
                memset(symbol->info.condinfo, 0,
                       sizeof(struct cond_info));
                break;
        case MACRO:
                symbol->info.macroinfo = 
                    (struct macro_info *)malloc(sizeof(struct macro_info));
                if (symbol->info.macroinfo == NULL) {
                        stop("Can't create macro info", EX_SOFTWARE);
                        /* NOTREACHED */
                }
                memset(symbol->info.macroinfo, 0,
                       sizeof(struct macro_info));
                STAILQ_INIT(&symbol->info.macroinfo->args);
                break;
        default:
                stop("Call to initialize_symbol with invalid symbol type",
                     EX_SOFTWARE);
                /* NOTREACHED */
                break;
        }
}

static void
add_macro_arg(const char *argtext, int argnum)
{
        struct macro_arg *marg;
        int i;
        int retval;
                

        if (cur_symbol == NULL || cur_symbol->type != MACRO) {
                stop("Invalid current symbol for adding macro arg",
                     EX_SOFTWARE);
                /* NOTREACHED */
        }

        marg = (struct macro_arg *)malloc(sizeof(*marg));
        if (marg == NULL) {
                stop("Can't create macro_arg structure", EX_SOFTWARE);
                /* NOTREACHED */
        }
        marg->replacement_text = NULL;
        retval = snprintf(regex_pattern, sizeof(regex_pattern),
                          "[^-/A-Za-z0-9_](%s)([^-/A-Za-z0-9_]|$)",
                          argtext);
        if (retval >= sizeof(regex_pattern)) {
                stop("Regex text buffer too small for arg",
                     EX_SOFTWARE);
                /* NOTREACHED */
        }
        retval = regcomp(&marg->arg_regex, regex_pattern, REG_EXTENDED);
        if (retval != 0) {
                stop("Regex compilation failed", EX_SOFTWARE);
                /* NOTREACHED */
        }
        STAILQ_INSERT_TAIL(&cur_symbol->info.macroinfo->args, marg, links);
}

static void
add_macro_body(const char *bodytext)
{
        if (cur_symbol == NULL || cur_symbol->type != MACRO) {
                stop("Invalid current symbol for adding macro arg",
                     EX_SOFTWARE);
                /* NOTREACHED */
        }
        cur_symbol->info.macroinfo->body = strdup(bodytext);
        if (cur_symbol->info.macroinfo->body == NULL) {
                stop("Can't duplicate macro body text", EX_SOFTWARE);
                /* NOTREACHED */
        }
}

static void
process_register(symbol_t **p_symbol)
{
        symbol_t *symbol = *p_symbol;

        if (symbol->type == UNINITIALIZED) {
                snprintf(errbuf, sizeof(errbuf), "Undefined register %s",
                         symbol->name);
                stop(errbuf, EX_DATAERR);
                /* NOTREACHED */
        } else if (symbol->type == ALIAS) {
                *p_symbol = symbol->info.ainfo->parent;
        } else if ((symbol->type != REGISTER)
                && (symbol->type != SCBLOC)
                && (symbol->type != SRAMLOC)) {
                snprintf(errbuf, sizeof(errbuf),
                         "Specified symbol %s is not a register",
                         symbol->name);
                stop(errbuf, EX_DATAERR);
        }
}

static void
format_1_instr(int opcode, symbol_ref_t *dest, expression_t *immed,
               symbol_ref_t *src, int ret)
{
        struct instruction *instr;
        struct ins_format1 *f1_instr;

        if (src->symbol == NULL)
                src = dest;

        /* Test register permissions */
        test_writable_symbol(dest->symbol);
        test_readable_symbol(src->symbol);

        /* Ensure that immediate makes sense for this destination */
        type_check(dest->symbol, immed, opcode);

        /* Allocate sequencer space for the instruction and fill it out */
        instr = seq_alloc();
        f1_instr = &instr->format.format1;
        f1_instr->ret = ret ? 1 : 0;
        f1_instr->opcode = opcode;
        f1_instr->destination = dest->symbol->info.rinfo->address
                              + dest->offset;
        f1_instr->source = src->symbol->info.rinfo->address
                         + src->offset;
        f1_instr->immediate = immed->value;

        if (is_download_const(immed))
                f1_instr->parity = 1;
        else if (dest->symbol == mode_ptr.symbol) {
                u_int src_value;
                u_int dst_value;

                /*
                 * Attempt to update mode information if
                 * we are operating on the mode register.
                 */
                if (src->symbol == allones.symbol)
                        src_value = 0xFF;
                else if (src->symbol == allzeros.symbol)
                        src_value = 0;
                else if (src->symbol == mode_ptr.symbol)
                        src_value = (dst_mode << 4) | src_mode;
                else
                        goto cant_update;

                switch (opcode) {
                case AIC_OP_AND:
                        dst_value = src_value & immed->value;
                        break;
                case AIC_OP_XOR:
                        dst_value = src_value ^ immed->value;
                        break;
                case AIC_OP_ADD:
                        dst_value = (src_value + immed->value) & 0xFF;
                        break;
                case AIC_OP_OR:
                        dst_value = src_value | immed->value;
                        break;
                case AIC_OP_BMOV:
                        dst_value = src_value;
                        break;
                default:
                        goto cant_update;
                }
                src_mode = dst_value & 0xF;
                dst_mode = (dst_value >> 4) & 0xF;
        }

cant_update:
        symlist_free(&immed->referenced_syms);
        instruction_ptr++;
}

static void
format_2_instr(int opcode, symbol_ref_t *dest, expression_t *places,
               symbol_ref_t *src, int ret)
{
        struct instruction *instr;
        struct ins_format2 *f2_instr;
        uint8_t shift_control;

        if (src->symbol == NULL)
                src = dest;

        /* Test register permissions */
        test_writable_symbol(dest->symbol);
        test_readable_symbol(src->symbol);

        /* Allocate sequencer space for the instruction and fill it out */
        instr = seq_alloc();
        f2_instr = &instr->format.format2;
        f2_instr->ret = ret ? 1 : 0;
        f2_instr->opcode = AIC_OP_ROL;
        f2_instr->destination = dest->symbol->info.rinfo->address
                              + dest->offset;
        f2_instr->source = src->symbol->info.rinfo->address
                         + src->offset;
        if (places->value > 8 || places->value <= 0) {
                stop("illegal shift value", EX_DATAERR);
                /* NOTREACHED */
        }
        switch (opcode) {
        case AIC_OP_SHL:
                if (places->value == 8)
                        shift_control = 0xf0;
                else
                        shift_control = (places->value << 4) | places->value;
                break;
        case AIC_OP_SHR:
                if (places->value == 8) {
                        shift_control = 0xf8;
                } else {
                        shift_control = (places->value << 4)
                                      | (8 - places->value)
                                      | 0x08;
                }
                break;
        case AIC_OP_ROL:
                shift_control = places->value & 0x7;
                break;
        case AIC_OP_ROR:
                shift_control = (8 - places->value) | 0x08;
                break;
        default:
                shift_control = 0; /* Quiet Compiler */
                stop("Invalid shift operation specified", EX_SOFTWARE);
                /* NOTREACHED */
                break;
        };
        f2_instr->shift_control = shift_control;
        symlist_free(&places->referenced_syms);
        instruction_ptr++;
}

static void
format_3_instr(int opcode, symbol_ref_t *src,
               expression_t *immed, symbol_ref_t *address)
{
        struct instruction *instr;
        struct ins_format3 *f3_instr;
        int addr;

        /* Test register permissions */
        test_readable_symbol(src->symbol);

        /* Ensure that immediate makes sense for this source */
        type_check(src->symbol, immed, opcode);

        /* Allocate sequencer space for the instruction and fill it out */
        instr = seq_alloc();
        f3_instr = &instr->format.format3;
        if (address->symbol == NULL) {
                /* 'dot' referrence.  Use the current instruction pointer */
                addr = instruction_ptr + address->offset;
        } else if (address->symbol->type == UNINITIALIZED) {
                /* forward reference */
                addr = address->offset;
                instr->patch_label = address->symbol;
        } else
                addr = address->symbol->info.linfo->address + address->offset;
        f3_instr->opcode = opcode;
        f3_instr->address = addr;
        f3_instr->source = src->symbol->info.rinfo->address
                         + src->offset;
        f3_instr->immediate = immed->value;

        if (is_download_const(immed))
                f3_instr->parity = 1;

        symlist_free(&immed->referenced_syms);
        instruction_ptr++;
}

static void
test_readable_symbol(symbol_t *symbol)
{
        
        if ((symbol->info.rinfo->modes & (0x1 << src_mode)) == 0) {
                snprintf(errbuf, sizeof(errbuf),
                        "Register %s unavailable in source reg mode %d",
                        symbol->name, src_mode);
                stop(errbuf, EX_DATAERR);
        }

        if (symbol->info.rinfo->mode == WO) {
                stop("Write Only register specified as source",
                     EX_DATAERR);
                /* NOTREACHED */
        }
}

static void
test_writable_symbol(symbol_t *symbol)
{
        
        if ((symbol->info.rinfo->modes & (0x1 << dst_mode)) == 0) {
                snprintf(errbuf, sizeof(errbuf),
                        "Register %s unavailable in destination reg mode %d",
                        symbol->name, dst_mode);
                stop(errbuf, EX_DATAERR);
        }

        if (symbol->info.rinfo->mode == RO) {
                stop("Read Only register specified as destination",
                     EX_DATAERR);
                /* NOTREACHED */
        }
}

static void
type_check(symbol_t *symbol, expression_t *expression, int opcode)
{
        symbol_node_t *node;
        int and_op;

        and_op = FALSE;
        if (opcode == AIC_OP_AND || opcode == AIC_OP_JNZ || AIC_OP_JZ)
                and_op = TRUE;

        /*
         * Make sure that we aren't attempting to write something
         * that hasn't been defined.  If this is an and operation,
         * this is a mask, so "undefined" bits are okay.
         */
        if (and_op == FALSE
         && (expression->value & ~symbol->info.rinfo->valid_bitmask) != 0) {
                snprintf(errbuf, sizeof(errbuf),
                         "Invalid bit(s) 0x%x in immediate written to %s",
                         expression->value & ~symbol->info.rinfo->valid_bitmask,
                         symbol->name);
                stop(errbuf, EX_DATAERR);
                /* NOTREACHED */
        }

        /*
         * Now make sure that all of the symbols referenced by the
         * expression are defined for this register.
         */
        if (symbol->info.rinfo->typecheck_masks != FALSE) {
                for(node = expression->referenced_syms.slh_first;
                    node != NULL;
                    node = node->links.sle_next) {
                        if ((node->symbol->type == MASK
                          || node->symbol->type == FIELD
                          || node->symbol->type == ENUM
                          || node->symbol->type == ENUM_ENTRY)
                         && symlist_search(&node->symbol->info.finfo->symrefs,
                                           symbol->name) == NULL) {
                                snprintf(errbuf, sizeof(errbuf),
                                         "Invalid field or mask %s "
                                         "for register %s",
                                         node->symbol->name, symbol->name);
                                stop(errbuf, EX_DATAERR);
                                /* NOTREACHED */
                        }
                }
        }
}

static void
make_expression(expression_t *immed, int value)
{
        SLIST_INIT(&immed->referenced_syms);
        immed->value = value & 0xff;
}

static void
add_conditional(symbol_t *symbol)
{
        static int numfuncs;

        if (numfuncs == 0) {
                /* add a special conditional, "0" */
                symbol_t *false_func;

                false_func = symtable_get("0");
                if (false_func->type != UNINITIALIZED) {
                        stop("Conditional expression '0' "
                             "conflicts with a symbol", EX_DATAERR);
                        /* NOTREACHED */
                }
                false_func->type = CONDITIONAL;
                initialize_symbol(false_func);
                false_func->info.condinfo->func_num = numfuncs++;
                symlist_add(&patch_functions, false_func, SYMLIST_INSERT_HEAD);
        }

        /* This condition has occurred before */
        if (symbol->type == CONDITIONAL)
                return;

        if (symbol->type != UNINITIALIZED) {
                stop("Conditional expression conflicts with a symbol",
                     EX_DATAERR);
                /* NOTREACHED */
        }

        symbol->type = CONDITIONAL;
        initialize_symbol(symbol);
        symbol->info.condinfo->func_num = numfuncs++;
        symlist_add(&patch_functions, symbol, SYMLIST_INSERT_HEAD);
}

static void
add_version(const char *verstring)
{
        const char prefix[] = " * ";
        int newlen;
        int oldlen;

        newlen = strlen(verstring) + strlen(prefix);
        oldlen = 0;
        if (versions != NULL)
                oldlen = strlen(versions);
        versions = realloc(versions, newlen + oldlen + 2);
        if (versions == NULL)
                stop("Can't allocate version string", EX_SOFTWARE);
        strcpy(&versions[oldlen], prefix);
        strcpy(&versions[oldlen + strlen(prefix)], verstring);
        versions[newlen + oldlen] = '\n';
        versions[newlen + oldlen + 1] = '\0';
}

void
yyerror(const char *string)
{
        stop(string, EX_DATAERR);
}

static int
is_download_const(expression_t *immed)
{
        if ((immed->referenced_syms.slh_first != NULL)
         && (immed->referenced_syms.slh_first->symbol->type == DOWNLOAD_CONST))
                return (TRUE);

        return (FALSE);
}