macross/emitBranch_68000.c

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2016-01-14 15:23:33 +00:00
/*
* Copyright (c) 1987 Fujitsu
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
/*
emitBranch_68000.c -- Routines to deal with code generation for
branches and jumps in the Macross assembler (68000
version).
Chip Morningstar -- Lucasfilm Ltd.
29-April-1985
*/
#include "macrossTypes.h"
#include "macrossGlobals.h"
/* emitRelativeBranch emits a relative branch instruction for the 68000,
branching from the current location given a condition to branch upon and a
target address. */
void
emitRelativeBranch(condition, target, fixupLocation)
conditionType condition;
valueType *target;
valueType *fixupLocation;
{
int i;
#define BCS_OPCODE 0x65
#define BCC_OPCODE 0x64
#define BEQ_OPCODE 0x67
#define BGE_OPCODE 0x6C
#define BGT_OPCODE 0x6E
#define BHI_OPCODE 0x62
#define BLE_OPCODE 0x6F
#define BLS_OPCODE 0x63
#define BLT_OPCODE 0x6D
#define BMI_OPCODE 0x6B
#define BNE_OPCODE 0x66
#define BPL_OPCODE 0x6A
#define BVC_OPCODE 0x68
#define BVS_OPCODE 0x69
#define BRA_OPCODE 0x60
static byte conditionalBranchOpcodes[] = {
/* CARRY_COND */ BCS_OPCODE,
/* EQUAL_COND */ BEQ_OPCODE,
/* OVERFLOW_COND */ BVS_OPCODE,
/* MINUS_COND */ BMI_OPCODE,
/* LT_COND */ BLT_OPCODE,
/* LEQ_COND */ BLE_OPCODE,
/* LOW_OR_SAME */ BLS_OPCODE,
/* ALWAYS_COND */ BRA_OPCODE,
/* NOT_CARRY_COND */ BCC_OPCODE,
/* NOT_EQUAL_COND */ BNE_OPCODE,
/* NOT_OVERFLOW_COND */ BVC_OPCODE,
/* PLUS_COND */ BPL_OPCODE,
/* GEQ_COND */ BGE_OPCODE,
/* GT_COND */ BGT_OPCODE,
/* HIGH_COND */ BHI_OPCODE,
/* NEVER_COND */ 0,
};
if (fixupLocation != NULL)
fixupLocation->value = -1;
if (condition == NEVER_COND)
return;
emitByte(conditionalBranchOpcodes[(int)condition]);
if (isByteOffset(target - (currentLocationCounter.value + 1))) {
if (fixupLocation != NULL)
*fixupLocation = currentLocationCounter;
emitRelativeByteOffset(target);
} else {
emitByte(0);
if (fixupLocation != NULL)
*fixupLocation = currentLocationCounter;
emitRelativeWordOffset(target);
}
}
/* emitJump emits a 68000 jump instruction given the target address */
simpleFixupListType *
emitJump(target, previousFixups)
valueType *target;
simpleFixupListType *previousFixups;
{
simpleFixupListType *result;
simpleFixupListType *buildSimpleFixupList();
#define JUMP_OPCODE_WORD 0x4EF8
#define JUMP_OPCODE_LONG 0x4EF9
#define JUMP_OPCODE_PC_REL 0x4EFA
result = previousFixups;
if (target == NULL) {
emitWord(JUMP_OPCODE_LONG);
result = buildSimpleFixupList(currentLocationCounter, result);
emitWord(0);
} else if (target->kindOfValue != ABSOLUTE_VALUE) {
emitWord(JUMP_OPCODE_LONG);
noteAnonymousReference();
emitLongValue(target);
} else if (isWordOffset(target->value-currentLocationCounter.value)) {
emitWord(JUMP_OPCODE_PC_REL);
emitWord(target->value - currentLocationCounter.value);
} else if (isWord(target)) {
emitWord(JUMP_OPCODE_WORD);
emitWord(target);
} else {
emitWord(JUMP_OPCODE_LONG);
emitLong(target);
}
return(result);
}