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