Subversion Repositories openrisc

/* is-div-test.S. l.div and l.divu instruction test of Or1ksim
 * 
 * Copyright (C) 1999-2006 OpenCores
 * Copyright (C) 2010 Embecosm Limited
 * 
 * Contributors various OpenCores participants
 * Contributor Jeremy Bennett <jeremy.bennett@embecosm.com>
 * 
 * This file is part of OpenRISC 1000 Architectural Simulator.
 * 
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 3 of the License, or (at your option)
 * any later version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 * 
 * You should have received a copy of the GNU General Public License along
 * with this program.  If not, see <http:  www.gnu.org/licenses/>.
 */

/* ----------------------------------------------------------------------------
 * Coding conventions
 *
 * A simple rising stack is provided starting at _stack and pointed to by
 * r1. r1 points to the next free word. Only 32-bit registers may be pushed
 * onto the stack.
 *
 * Local labels up to 49 are reserved for macros. Each is used only once in
 * all macros. You can get in a serious mess if you get local label clashing
 * in macros.
 *
 * Arguments to functions are passed in r3 through r8.
 * r9 is the link (return address)
 * r11 is for returning results
 *
 * Only r1 and r2 are preserved across function calls. It is up to the callee
 * to save any other registers required.
 * ------------------------------------------------------------------------- */

/* ----------------------------------------------------------------------------
 * Test coverage
 *
 * The l.div and l.divu instructions should set the carry flag as well as
 * triggering an event when divide by zero occurs.
 *
 * Having fixed the problem, this is (in good software engineering style), a
 * regresison test to go with the fix.
 *
 * This is not a comprehensive test of either instruction (yet).
 *
 * Of course what is really needed is a comprehensive instruction test...
 * ------------------------------------------------------------------------- */


#include "inst-set-test.h"

/* ----------------------------------------------------------------------------
 * Test of divide l.div
 * ------------------------------------------------------------------------- */

        .section .text
        .global _start
_start:
        /* Signed divide by zero */
_div:   
        LOAD_STR (r3, "l.div\n")
        l.jal   _puts
        l.nop

        LOAD_CONST (r2, ~SPR_SR_CY)     /* Clear the carry flag */
        l.mfspr r3,r0,SPR_SR
        l.and   r3,r3,r2
        l.mtspr r0,r3,SPR_SR

        LOAD_CONST (r5,1)               /* Set up args for division */
        LOAD_CONST (r6,0)
        l.div   r4,r5,r6

        l.mfspr r2,r0,SPR_SR            /* So we can examine the carry flag */
        LOAD_CONST (r4, SPR_SR_CY)      /* The carry bit */
        l.and   r2,r2,r4
        l.sfeq  r2,r4
        CHECK_FLAG ("1 / 0 (with error) carry flag set: ", TRUE)

        /* Signed divide by zero */
_divu:  
        LOAD_STR (r3, "l.divu\n")
        l.jal   _puts
        l.nop

        LOAD_CONST (r2, ~SPR_SR_CY)     /* Clear the carry flag */
        l.mfspr r3,r0,SPR_SR
        l.and   r3,r3,r2
        l.mtspr r0,r3,SPR_SR

        LOAD_CONST (r5,1)               /* Set up args for division */
        LOAD_CONST (r6,0)
        l.divu  r4,r5,r6

        l.mfspr r2,r0,SPR_SR            /* So we can examine the carry flag */
        LOAD_CONST (r4, SPR_SR_CY)      /* The carry bit */
        l.and   r2,r2,r4
        l.sfeq  r2,r4
        CHECK_FLAG ("1 / 0 (with error) carry flag set: ", TRUE)

/* ----------------------------------------------------------------------------
 * All done
 * ------------------------------------------------------------------------- */
_exit:
        LOAD_STR (r3, "Test completed\n")
        l.jal   _puts
        l.nop

        TEST_EXIT