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# Copyright (c) 2003  Red Hat, Inc. All rights reserved.
#
# This copyrighted material is made available to anyone wishing to use, modify,
# copy, or redistribute it subject to the terms and conditions of the BSD 
# License.   This program is distributed in the hope that it will be useful, 
# but WITHOUT ANY WARRANTY expressed or implied, including the implied 
# warranties of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  A copy of
# this license is available at http://www.opensource.org/licenses. Any Red Hat 
# trademarks that are incorporated in the source code or documentation are not
# subject to the BSD License and may only be used or replicated with the express
# permission of Red Hat, Inc.
#
# Toshiba Media Processor startup file (crt0.S)
#
# Designed for user programs running in the 0-2Mb startup section.
# Designed for the simulator by default.
#
# Exception/Interrupt Handler Locations 
# CFG.EVM  CFG.EVA  CFG.IVA   Exception     INTn
## 0         -        -        0x0000_0000  0x0000_0030 rom
## 1         0        0        0x0020_0000  0x0020_0030 local RAM / local RAM
## 1         1        0        0x0080_0000  0x0020_0000 ext RAM / local RAM
## 1         0        1        0x0020_0000  0x0080_0000 local RAM / ext RAM
## 1         1        1        0x0080_0000  0x0080_0030 ext RAM / ext RAM
#
# Exceptions            
# Reset 0x0000_0000
# NMI   0x0000_0000+4
# RI    (Base Address) +0x08
# ZDIV  (Base Address) +0x0C
# BRK   (Base Address) +0x10
# SWI   (Base Address) +0x14
# DSP   (Base Address) +0x1C
# COP   (Base Address) +0x20

        .set _local_ram_base, 0x00200000
        .set _ext_ram_base, 0x00800000
        .set _int_base_offset, 0x30

#include "syscall.h"

.macro  if_bitfield_zero reg, start, length, label
        ldc     $0, \reg
        srl     $0, \start
        and3    $0, $0, (1 << \length) - 1
        beqz    $0,\label
.endm

.macro  if_bitfield_notN reg, start, length, N, label
        ldc     $0, \reg
        srl     $0, \start
        and3    $0, $0, (1 << \length) - 1
        bnei    $0,\N, \label
.endm
        
.macro  if_bitfield_eqN reg, start, length, N, label
        ldc     $0, \reg
        srl     $0, \start
        and3    $0, $0, (1 << \length) - 1
        beqi    $0,\N, \label
.endm

.macro  if_bitfield_ltN reg, start, length, N, label
        ldc     $0, \reg
        srl     $0, \start
        and3    $0, $0, (1 << \length) - 1
        blti    $0,\N, \label
.endm

        .section  .hwinit, "ax"
        # CCFG.ICSZ
        if_bitfield_zero reg=$ccfg, start=16, length=7, label=.Lend_enable_icache
__enable_icache:
        # set ICE(cfg[1])
        ldc     $1,$cfg
        or3     $1,$1,2
        stc     $1,$cfg
        nop
        nop
        nop
        nop
        nop
.Lend_enable_icache:
        ret

__enable_dcache:
        # CCFG.DCSZ
        if_bitfield_zero reg=$ccfg, start=0, length=7, label=.Lend_enable_dcache
        # set DCE(cfg[0])
        ldc     $1,$cfg
        or3     $1,$1,1
        stc     $1,$cfg
        nop
        nop
        nop
        nop
        nop
        ret
.Lend_enable_dcache:            

        .text

#ifdef NOVEC
        .global _reset
_reset:
#endif

        .global _start
_start:
        mov     $fp, 0                  # for unwinding

        # $sp set
        movh    $sp, %uhi(__stack_table)
        or3     $sp, $sp, %lo(__stack_table)

        # initialize sp, gp, tp
        # get CPU ID
        ldc     $0, $id
        srl     $0, 16

        # load ID-specific stack pointer        
        sl2ad3  $0, $0, $sp              # $0 = ($0 << 2) + $sp
        lw      $sp,($0)                 # $sp = *($0)
        mov     $0,0xfffffff8
        and     $sp, $0

#ifndef NOVEC
        # copy exception vector table

        # RCFG.IRSZ
        if_bitfield_zero reg=$rcfg, start=16, length=7, label=.Lend_ev_imem
        # handle imem
        movh    $11,%uhi(_local_ram_base)
        or3     $11,$11,%lo(_local_ram_base)
        # clear CFG.EVA ([23])
        ldc     $0,$cfg
        movh    $1, %uhi(0xff7fffff)
        or3     $1, $1, %lo(0xff7fffff)
        and     $0,$1
        stc     $0,$cfg
        bra     .Ldo_repeat_ev
.Lend_ev_imem:  
#ifdef     UseSDRAM
        movh    $11,%uhi(_ext_ram_base)
        or3     $11,$11,%lo(_ext_ram_base)
        # set CFG.EVA ([23])
        ldc     $0,$cfg
        movh    $1,%uhi(1<<23)
        or3     $1,$1,%lo(1<<23)
        or      $0,$1
        stc     $0,$cfg
#else
        # handle ROM
        bra     .Lend_ev
#endif
.Ldo_repeat_ev: 
        # set CFG.EVM ([4])
        ldc     $0,$cfg
        or3     $0,$0,(1<<4)
        stc     $0,$cfg
        # copy _exception_table to $11
        movh    $12,%uhi(_exception_table)
        or3     $12,$12,%lo(_exception_table)
        mov     $13,8
        repeat  $13,.Lrepeat_ev
        lw      $1,0($12)
        add     $12,4
.Lrepeat_ev:
        sw      $1,0($11)
        add     $11,4
.Lend_ev:       

        # copy interrupt vector table
        # RCFG.IRSZ
        if_bitfield_zero reg=$rcfg, start=16, length=7, label=.Lend_iv_imem
        # handle imem
        movh    $11,%uhi(_local_ram_base)
        or3     $11,$11,%lo(_int_base_offset)
        # clear CFG.IVA ([22])
        ldc     $0,$cfg
        movh    $1,%uhi(0xffbfffff)  # ~(1<<22)
        or3     $1,$1,%lo(0xffbfffff)
        and     $0,$1
        stc     $0,$cfg
        bra     .Ldo_repeat_iv
.Lend_iv_imem:  
#ifdef UseSDRAM
        movh    $11,%uhi(_ext_ram_base)
        or3     $11,$11,%lo(_int_base_offset)
        # set CFG. IVA ([22])
        ldc     $0,$cfg
        movh    $1,%uhi(1<<22)
        or3     $1,$1,%lo(1<<22)
        or      $0,$1
        stc     $0,$cfg
#else
        # handle ROM
        bra     .Lend_iv
#endif
.Ldo_repeat_iv:
        # set CFG.IVM ([3])
        ldc     $0,$cfg
        or3     $0,$0,(1<<3)
        stc     $0,$cfg
        # copy _interrupt_table to $11
        movh    $12,%uhi(_interrupt_table)
        or3     $12,$12,%lo(_interrupt_table)
        mov     $13,32
        add     $13,-1
        and3    $13,$13,127
        repeat  $13,.Lrepeat_iv
        lw      $1,0($12)
        add     $12,4
.Lrepeat_iv:
        sw      $1,0($11)
        add     $11,4
.Lend_iv:       

        # initialize instruction cache
        # Icache Size CCFG.ICSZ ([22..16]) KByte
        if_bitfield_zero reg=$ccfg, start=16, length=7, label=.Lend_ic
        mov     $3,$0                   # cache size in KB
        # ID.ID
        if_bitfield_ltN reg=$ID, start=8, length=8, N=3, label=.Lend_mepc3_ic
        # Line Size CCFG.ICSZ ([26..24]) Byte
        if_bitfield_ltN reg=$ccfg, start=24, length=3, N=2, label=.Lend_ic
        bgei    $0,5,.Lend_ic

        add3    $1,$0,3                 # bit width of line size
        mov     $0,$3
        # clear tag
        mov     $2,10
        sub     $2,$1
        sll     $0,$2                   # *KByte/(line size)    
        add     $0,-1
        mov     $2,1
        sll     $2,$1                   # line size
        bra     .Ldo_repeat_icache
.Lend_mepc3_ic:
        # ICache: $0 KByte
        mov     $0,$3
        # clear tag
        sll     $0,(10-5)               # *KByte/(32byte=linesize)
        add     $0,-1
        mov     $2,32
.Ldo_repeat_icache:     
        mov     $1,0
        bra     0f
        # Align this code on an 8 byte boundary in order to keep the repeat
        # loop entirely within the instruction fetch buffer.
        .p2align 3
0:
        movh    $3,%hi(0x00310000)      # for tag
        repeat  $0,.Lrepeat_icache
        add     $0,-1
.Lrepeat_icache:
        sw      $1,0($3)
        add3    $3,$3,$2
.Lenable_icache:
        movh    $1,%hi(__enable_icache)
        add3    $1,$1,%lo(__enable_icache)
        jsr     $1
.Lend_ic:

        # initialize data cache
        # Dcache Size CCFG.DCSZ ([6..0]) KByte
        if_bitfield_zero reg=$ccfg, start=0, length=7, label=.Lend_dc
        mov     $3,$0                   # cache size in KB
        # ID.ID
        if_bitfield_ltN reg=$ID, start=8, length=8, N=3, label=.Lend_mepc3_dc
        # Line Size CCFG.DCSZ ([10..8]) Byte
        if_bitfield_ltN reg=$ccfg, start=8, length=3, N=2, label=.Lend_dc
        bgei    $0,5,.Lend_dc

        add3    $1,$0,3                 # bit width of line size
        mov     $0,$3
        # clear tag
        mov     $2,10
        sub     $2,$1
        sll     $0,$2                   # *KByte/(line size)    
        add     $0,-1
        mov     $2,1
        sll     $2,$1                   # line size
        bra     .Ldo_repeat_dcache
.Lend_mepc3_dc: 
        # DCache: $0 KByte
        mov     $0,$3
        # clear tag
        sll     $0,(10-5)               # *KByte/(32byte=linesize)
        add     $0,-1
        mov     $2,32
.Ldo_repeat_dcache:
        mov     $1,0
        movh    $3,%hi(0x00330000)              # for tag

        repeat  $0,.Lrepeat_dcache
        add     $0,-1
.Lrepeat_dcache:
        sw      $1,0($3)
        add3    $3,$3,$2
.Lenable_dcache:
        movh    $1,%hi(__enable_dcache)
        add3    $1,$1,%lo(__enable_dcache)
        jsr             $1
.Lend_dc:       
        # NOVEC 
#endif
        mov     $0, 0
        
        movh    $gp, %uhi(__sdabase)
        or3     $gp, $gp, %lo(__sdabase)

        movh    $tp, %uhi(__tpbase)
        or3     $tp, $tp, %lo(__tpbase)

        # zero out BSS
        movh    $1, %uhi(__bss_start)
        or3     $1, $1, %lo(__bss_start)
        mov     $2, 0
        movh    $3, %uhi(_end)
        or3     $3, $3, %lo(_end)
        sub     $3, $1
        bsr     memset

        movh    $1, %uhi(__sbss_start)
        or3     $1, $1, %lo(__sbss_start)
        mov     $2, 0
        movh    $3, %uhi(__sbss_end)
        or3     $3, $3, %lo(__sbss_end)
        sub     $3, $1
        bsr     memset

        movh    $1, %uhi(__farbss_start)
        or3     $1, $1, %lo(__farbss_start)
        mov     $2, 0
        movh    $3, %uhi(__farbss_end)
        or3     $3, $3, %lo(__farbss_end)
        sub     $3, $1
        bsr     memset

    # enable interrupts
    ei

    # construct global class variables
        bsr     __invoke_init_section

    # invoke main
        mov     $1, 0                   # argc, argv, envp
        mov     $2, 0
        mov     $3, 0
        bsr     main
        mov     $1, $0
        bsr     exit

        .global _exit
_exit:
        # Prevent _exit recursion
        movh    $3, %uhi(_exit_in_progress)
        or3     $3, $3, %lo(_exit_in_progress)
        lw      $5, ($3)
        bnez    $5, _skip_fini
        mov     $5, 1   
        sw      $5, ($3)
        
        # We don't need to preserve $5 because we're going to exit anyway.
        mov     $5,$1

    # destruct global class variables
        bsr     __invoke_fini_section
        mov     $1,$5

_skip_fini:

#ifdef NOSIM
_exit_loop:
        bra     _exit_loop
#else
        .2byte 0x7800 | ((SYS_exit & 0xe) << 7) | ((SYS_exit & 1) << 4)
        ret
#endif

        .data
_exit_in_progress:      .word 0

                
        
# For these two, the epilogue is in crtn.S

        .section        .init
__invoke_init_section:
        add     $sp, -8
        ldc     $0, $lp
        sw      $0, ($sp)

        .section .fini
__invoke_fini_section:
        add     $sp, -8
        ldc     $0, $lp
        sw      $0, ($sp)

#ifndef NOVEC
        .section .vec, "ax"
        .core
        .org 0x0, 0
    .global _exception_table
.type   _exception_table,@function      
_exception_table:       
        .p2align 2
    .org 0x0000, 0
        .global _reset
_reset:
        jmp  _handler_RESET
    .org 0x0004, 0
        jmp  _handler_NMI
    .org 0x0008, 0
        jmp  _handler_RI
    .org 0x000c, 0
        jmp  _handler_ZDIV
    .org 0x0010, 0
        jmp  _handler_BRK
    .org 0x0014, 0
        jmp  _handler_SWI
    .org 0x0018, 0
        jmp  _handler_DEBUG
    .org 0x001c, 0
        jmp  _handler_DSP
    .org 0x0020, 0
        jmp  _handler_COP

        .org 0x30, 0
        .global _interrupt_table
.type   _interrupt_table,@function      
_interrupt_table:               
    .org 0x0030
        jmp  _handler_INT0
    .org 0x0034
        jmp  _handler_INT1
    .org 0x0038
        jmp  _handler_INT2
    .org 0x003c
        jmp  _handler_INT3
    .org 0x0040
        jmp  _handler_INT4
    .org 0x0044
        jmp  _handler_INT5
    .org 0x0048
        jmp  _handler_INT6
    .org 0x004c
        jmp  _handler_INT7
    .org 0x0050
        jmp  _handler_INT8
    .org 0x0054
        jmp  _handler_INT9
    .org 0x0058
        jmp  _handler_INT10
    .org 0x005c
        jmp  _handler_INT11
    .org 0x0060
        jmp  _handler_INT12
    .org 0x0064
        jmp  _handler_INT13
    .org 0x0068
        jmp  _handler_INT14
    .org 0x006c
        jmp  _handler_INT15
    .org 0x0070
        jmp  _handler_INT16
    .org 0x0074
        jmp  _handler_INT17
    .org 0x0078
        jmp  _handler_INT18
    .org 0x007c
        jmp  _handler_INT19
    .org 0x0080
        jmp  _handler_INT20
    .org 0x0084
        jmp  _handler_INT21
    .org 0x0088
        jmp  _handler_INT22
    .org 0x008c
        jmp  _handler_INT23
    .org 0x0090
        jmp  _handler_INT24
    .org 0x0094
        jmp  _handler_INT25
    .org 0x0098
        jmp  _handler_INT26
    .org 0x009c
        jmp  _handler_INT27
    .org 0x00a0
        jmp  _handler_INT28
    .org 0x00a4
        jmp  _handler_INT29
    .org 0x00a8
        jmp  _handler_INT30
    .org 0x00ac
        jmp  _handler_INT31
        # NOVEC 
#endif