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[/] [amber/] [trunk/] [hw/] [tests/] [change_mode.S] - Rev 66
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/*****************************************************************
// //
// Amber 2 Core Instruction Test //
// //
// This file is part of the Amber project //
// http://www.opencores.org/project,amber //
// //
// Description //
// Tests teq, tst, cmp and cmn with the p flag set //
// Starts in supervisor mode, changes to Interrupt mode, //
// then Fast Interrupt mode, then supervisor mode again //
// and finally User mode //
// //
// Author(s): //
// - Conor Santifort, csantifort.amber@gmail.com //
// //
//////////////////////////////////////////////////////////////////
// //
// Copyright (C) 2010 Authors and OPENCORES.ORG //
// //
// This source file may be used and distributed without //
// restriction provided that this copyright statement is not //
// removed from the file and that any derivative work contains //
// the original copyright notice and the associated disclaimer. //
// //
// This source file is free software; you can redistribute it //
// and/or modify it under the terms of the GNU Lesser General //
// Public License as published by the Free Software Foundation; //
// either version 2.1 of the License, or (at your option) any //
// later version. //
// //
// This source 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 Lesser General Public License for more //
// details. //
// //
// You should have received a copy of the GNU Lesser General //
// Public License along with this source; if not, download it //
// from http://www.opencores.org/lgpl.shtml //
// //
*****************************************************************/
#include "amber_registers.h"
.section .text
.globl main
main:
@ ------------------------------------------------------------
@ Change to Interrupt mode using tstp
@ tstp does an AND
mov r4, #0xfffffffe
@ When the pc is in the rn position, it includes the status bits
tstp r4, pc
@ Check that we're now in Interrupt mode
mov r5, pc
@ just want the mode bits
and r5, r5, #0x3
cmp r5, #2
movne r10, #50
bne testfail
@ ------------------------------------------------------------
@ Change to Fast Interrupt mode using cmpp
@ cmpp does a subtract
mov r6, pc
cmpp r6, #1
mov r7, pc
and r8, r7, #3
cmp r8, #1
movne r10, #60
bne testfail
@ ------------------------------------------------------------
@ Change back to Supervisor mode using cmnp
@ cmnp does an add
ldr r1, Status1
cmnp pc, #0xf0000003
nop
mov r9, pc
ldr r0, PCMask
bic r13, r9, r0
cmp r13, r1
movne r10, #70
bne testfail
@ ------------------------------------------------------------
@ Clear all the status bits and change to user mode
@ teq does an XOR
teqp pc, #0
b 1f
b testfail
b testfail
@ Check that all the status bits are now zero
1: ldr r0, PCMask
mov r1, pc
bics r1, r1, r0
movne r10, #10
bne testfail
@ ------------------------------------------------------------
@ Now in user mode, so can't change back to supervisor mode
@ But can set the condition flags
teqp pc, #0xf0000003
mov r2, #0
orr r1, r2, pc
bic r1, r1, r0
cmp r1, #0xf0000000
movne r10, #20
bne testfail
b testpass
testfail:
ldr r11, AdrTestStatus
str r10, [r11]
b testfail
testpass:
ldr r11, AdrTestStatus
mov r10, #17
str r10, [r11]
b testpass
/* Write 17 to this address to generate a Test Passed message */
AdrTestStatus: .word ADR_AMBER_TEST_STATUS
PCMask: .word 0x03fffffc
Status1: .word 0xf0000003
/* ========================================================================= */
/* ========================================================================= */
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