mgba/src/sm83/decoder.c

585 lines
17 KiB
C

/* Copyright (c) 2013-2017 Jeffrey Pfau
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include <mgba/internal/sm83/decoder.h>
#include <mgba/internal/sm83/emitter-sm83.h>
#include <mgba/internal/sm83/sm83.h>
#include <mgba-util/string.h>
typedef size_t (*SM83Decoder)(uint8_t opcode, struct SM83InstructionInfo* info);
#define DEFINE_DECODER_SM83(NAME, BODY) \
static size_t _SM83Decode ## NAME (uint8_t opcode, struct SM83InstructionInfo* info) { \
UNUSED(opcode); \
info->mnemonic = SM83_MN_RST; \
BODY; \
return 0; \
}
DEFINE_DECODER_SM83(NOP, info->mnemonic = SM83_MN_NOP;)
#define DEFINE_LD_DECODER_SM83_NOHL(NAME) \
DEFINE_DECODER_SM83(LD ## NAME ## _A, \
info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_ ## NAME; \
info->op2.reg = SM83_REG_A) \
DEFINE_DECODER_SM83(LD ## NAME ## _B, \
info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_ ## NAME; \
info->op2.reg = SM83_REG_B) \
DEFINE_DECODER_SM83(LD ## NAME ## _C, \
info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_ ## NAME; \
info->op2.reg = SM83_REG_C) \
DEFINE_DECODER_SM83(LD ## NAME ## _D, \
info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_ ## NAME; \
info->op2.reg = SM83_REG_D) \
DEFINE_DECODER_SM83(LD ## NAME ## _E, \
info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_ ## NAME; \
info->op2.reg = SM83_REG_E) \
DEFINE_DECODER_SM83(LD ## NAME ## _H, \
info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_ ## NAME; \
info->op2.reg = SM83_REG_H) \
DEFINE_DECODER_SM83(LD ## NAME ## _L, \
info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_ ## NAME; \
info->op2.reg = SM83_REG_L)
#define DEFINE_LD_DECODER_SM83_MEM(NAME, REG) \
DEFINE_DECODER_SM83(LD ## NAME ## _ ## REG, info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_ ## NAME; \
info->op2.reg = SM83_REG_ ## REG; \
info->op2.flags = SM83_OP_FLAG_MEMORY;)
#define DEFINE_LD_DECODER_SM83_MEM_2(NAME, REG) \
DEFINE_DECODER_SM83(LD ## REG ## _ ## NAME, info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_ ## REG; \
info->op1.flags = SM83_OP_FLAG_MEMORY; \
info->op2.reg = SM83_REG_ ## NAME;)
#define DEFINE_LD_DECODER_SM83(NAME) \
DEFINE_LD_DECODER_SM83_MEM(NAME, HL) \
DEFINE_LD_DECODER_SM83_MEM_2(NAME, HL) \
DEFINE_DECODER_SM83(LD ## NAME ## _, info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_ ## NAME; \
return 1;) \
DEFINE_LD_DECODER_SM83_NOHL(NAME)
#define DEFINE_LD_2_DECODER_SM83(NAME) \
DEFINE_DECODER_SM83(LD ## NAME, info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_ ## NAME; \
return 2;)
DEFINE_LD_DECODER_SM83(B);
DEFINE_LD_DECODER_SM83(C);
DEFINE_LD_DECODER_SM83(D);
DEFINE_LD_DECODER_SM83(E);
DEFINE_LD_DECODER_SM83(H);
DEFINE_LD_DECODER_SM83(L);
DEFINE_LD_DECODER_SM83(A);
DEFINE_LD_DECODER_SM83_MEM(A, BC);
DEFINE_LD_DECODER_SM83_MEM(A, DE);
DEFINE_LD_2_DECODER_SM83(BC);
DEFINE_LD_2_DECODER_SM83(DE);
DEFINE_LD_2_DECODER_SM83(HL);
DEFINE_LD_2_DECODER_SM83(SP);
DEFINE_DECODER_SM83(LDHL_, \
info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_HL; \
info->op1.flags = SM83_OP_FLAG_MEMORY; \
return 1;)
DEFINE_DECODER_SM83(LDHL_SP, \
info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_HL; \
info->op2.reg = SM83_REG_SP; \
return 1;)
DEFINE_DECODER_SM83(LDSP_HL, \
info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_SP; \
info->op2.reg = SM83_REG_HL;)
DEFINE_DECODER_SM83(LDAIOC, \
info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_A; \
info->op2.reg = SM83_REG_C; \
info->op2.immediate = 0xFF00; \
info->op2.flags = SM83_OP_FLAG_MEMORY;)
DEFINE_DECODER_SM83(LDIOCA, \
info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_C; \
info->op1.immediate = 0xFF00; \
info->op1.flags = SM83_OP_FLAG_MEMORY; \
info->op2.reg = SM83_REG_A;)
DEFINE_DECODER_SM83(LDAIO, \
info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_A; \
info->op2.immediate = 0xFF00; \
info->op2.flags = SM83_OP_FLAG_MEMORY; \
return 1;)
DEFINE_DECODER_SM83(LDIOA, \
info->mnemonic = SM83_MN_LD; \
info->op1.immediate = 0xFF00; \
info->op1.flags = SM83_OP_FLAG_MEMORY; \
info->op2.reg = SM83_REG_A; \
return 1;)
#define DEFINE_ALU_DECODER_SM83_NOHL(NAME) \
DEFINE_DECODER_SM83(NAME ## A, info->mnemonic = SM83_MN_ ## NAME; info->op1.reg = SM83_REG_A) \
DEFINE_DECODER_SM83(NAME ## B, info->mnemonic = SM83_MN_ ## NAME; info->op1.reg = SM83_REG_B) \
DEFINE_DECODER_SM83(NAME ## C, info->mnemonic = SM83_MN_ ## NAME; info->op1.reg = SM83_REG_C) \
DEFINE_DECODER_SM83(NAME ## D, info->mnemonic = SM83_MN_ ## NAME; info->op1.reg = SM83_REG_D) \
DEFINE_DECODER_SM83(NAME ## E, info->mnemonic = SM83_MN_ ## NAME; info->op1.reg = SM83_REG_E) \
DEFINE_DECODER_SM83(NAME ## H, info->mnemonic = SM83_MN_ ## NAME; info->op1.reg = SM83_REG_H) \
DEFINE_DECODER_SM83(NAME ## L, info->mnemonic = SM83_MN_ ## NAME; info->op1.reg = SM83_REG_L)
#define DEFINE_ALU_DECODER_SM83_MEM(NAME, REG) \
DEFINE_DECODER_SM83(NAME ## REG, info->mnemonic = SM83_MN_ ## NAME; \
info->op1.reg = SM83_REG_HL; \
info->op1.flags = SM83_OP_FLAG_MEMORY;)
#define DEFINE_ALU_DECODER_SM83(NAME) \
DEFINE_ALU_DECODER_SM83_MEM(NAME, HL) \
DEFINE_DECODER_SM83(NAME, info->mnemonic = SM83_MN_ ## NAME; \
info->op1.reg = SM83_REG_A; \
info->op1.flags = SM83_OP_FLAG_IMPLICIT; \
return 1;) \
DEFINE_ALU_DECODER_SM83_NOHL(NAME)
DEFINE_ALU_DECODER_SM83_NOHL(INC);
DEFINE_ALU_DECODER_SM83_NOHL(DEC);
DEFINE_ALU_DECODER_SM83(AND);
DEFINE_ALU_DECODER_SM83(XOR);
DEFINE_ALU_DECODER_SM83(OR);
DEFINE_ALU_DECODER_SM83(CP);
DEFINE_ALU_DECODER_SM83(ADD);
DEFINE_ALU_DECODER_SM83(ADC);
DEFINE_ALU_DECODER_SM83(SUB);
DEFINE_ALU_DECODER_SM83(SBC);
#define DEFINE_ALU_DECODER_SM83_ADD_HL(REG) \
DEFINE_DECODER_SM83(ADDHL_ ## REG, info->mnemonic = SM83_MN_ADD; \
info->op1.reg = SM83_REG_HL; \
info->op2.reg = SM83_REG_ ## REG;)
DEFINE_ALU_DECODER_SM83_ADD_HL(BC)
DEFINE_ALU_DECODER_SM83_ADD_HL(DE)
DEFINE_ALU_DECODER_SM83_ADD_HL(HL)
DEFINE_ALU_DECODER_SM83_ADD_HL(SP)
DEFINE_DECODER_SM83(ADDSP, info->mnemonic = SM83_MN_ADD; \
info->op1.reg = SM83_REG_SP; \
return 1;)
#define DEFINE_CONDITIONAL_DECODER_SM83(NAME) \
DEFINE_ ## NAME ## _INSTRUCTION_SM83(, 0) \
DEFINE_ ## NAME ## _INSTRUCTION_SM83(C, SM83_COND_C) \
DEFINE_ ## NAME ## _INSTRUCTION_SM83(Z, SM83_COND_Z) \
DEFINE_ ## NAME ## _INSTRUCTION_SM83(NC, SM83_COND_NC) \
DEFINE_ ## NAME ## _INSTRUCTION_SM83(NZ, SM83_COND_NZ)
#define DEFINE_JP_INSTRUCTION_SM83(CONDITION_NAME, CONDITION) \
DEFINE_DECODER_SM83(JP ## CONDITION_NAME, \
info->mnemonic = SM83_MN_JP; \
info->condition = CONDITION; \
return 2;)
#define DEFINE_JR_INSTRUCTION_SM83(CONDITION_NAME, CONDITION) \
DEFINE_DECODER_SM83(JR ## CONDITION_NAME, \
info->mnemonic = SM83_MN_JR; \
info->condition = CONDITION; \
info->op1.flags = SM83_OP_FLAG_RELATIVE; \
return 1;)
#define DEFINE_CALL_INSTRUCTION_SM83(CONDITION_NAME, CONDITION) \
DEFINE_DECODER_SM83(CALL ## CONDITION_NAME, \
info->mnemonic = SM83_MN_CALL; \
info->condition = CONDITION; \
return 2;)
#define DEFINE_RET_INSTRUCTION_SM83(CONDITION_NAME, CONDITION) \
DEFINE_DECODER_SM83(RET ## CONDITION_NAME, \
info->mnemonic = SM83_MN_RET; \
info->condition = CONDITION;)
DEFINE_CONDITIONAL_DECODER_SM83(JP);
DEFINE_CONDITIONAL_DECODER_SM83(JR);
DEFINE_CONDITIONAL_DECODER_SM83(CALL);
DEFINE_CONDITIONAL_DECODER_SM83(RET);
DEFINE_DECODER_SM83(JPHL, \
info->mnemonic = SM83_MN_JP; \
info->op1.reg = SM83_REG_HL)
DEFINE_DECODER_SM83(RETI, info->mnemonic = SM83_MN_RETI)
DEFINE_DECODER_SM83(LDBC_A, \
info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_BC; \
info->op1.flags = SM83_OP_FLAG_MEMORY; \
info->op2.reg = SM83_REG_A;)
DEFINE_DECODER_SM83(LDDE_A, \
info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_DE; \
info->op1.flags = SM83_OP_FLAG_MEMORY; \
info->op2.reg = SM83_REG_A;)
DEFINE_DECODER_SM83(LDIA, \
info->mnemonic = SM83_MN_LD; \
info->op1.flags = SM83_OP_FLAG_MEMORY; \
info->op2.reg = SM83_REG_A; \
return 2;)
DEFINE_DECODER_SM83(LDAI, \
info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_A; \
info->op2.flags = SM83_OP_FLAG_MEMORY; \
return 2;)
DEFINE_DECODER_SM83(LDISP, \
info->mnemonic = SM83_MN_LD; \
info->op1.flags = SM83_OP_FLAG_MEMORY; \
info->op2.reg = SM83_REG_SP; \
return 2;)
DEFINE_DECODER_SM83(LDIHLA, \
info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_HL; \
info->op1.flags = SM83_OP_FLAG_INCREMENT | SM83_OP_FLAG_MEMORY; \
info->op2.reg = SM83_REG_A;)
DEFINE_DECODER_SM83(LDDHLA, \
info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_HL; \
info->op1.flags = SM83_OP_FLAG_DECREMENT | SM83_OP_FLAG_MEMORY; \
info->op2.reg = SM83_REG_A;)
DEFINE_DECODER_SM83(LDA_IHL, \
info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_A; \
info->op2.reg = SM83_REG_HL; \
info->op2.flags = SM83_OP_FLAG_INCREMENT | SM83_OP_FLAG_MEMORY;)
DEFINE_DECODER_SM83(LDA_DHL, \
info->mnemonic = SM83_MN_LD; \
info->op1.reg = SM83_REG_A; \
info->op2.reg = SM83_REG_HL; \
info->op2.flags = SM83_OP_FLAG_DECREMENT | SM83_OP_FLAG_MEMORY;)
#define DEFINE_INCDEC_WIDE_INSTRUCTION_SM83(REG) \
DEFINE_DECODER_SM83(INC ## REG, info->mnemonic = SM83_MN_INC; info->op1.reg = SM83_REG_ ## REG) \
DEFINE_DECODER_SM83(DEC ## REG, info->mnemonic = SM83_MN_DEC; info->op1.reg = SM83_REG_ ## REG)
DEFINE_INCDEC_WIDE_INSTRUCTION_SM83(BC);
DEFINE_INCDEC_WIDE_INSTRUCTION_SM83(DE);
DEFINE_INCDEC_WIDE_INSTRUCTION_SM83(HL);
DEFINE_INCDEC_WIDE_INSTRUCTION_SM83(SP);
DEFINE_DECODER_SM83(INC_HL,
info->mnemonic = SM83_MN_INC;
info->op1.reg = SM83_REG_HL;
info->op1.flags = SM83_OP_FLAG_MEMORY;)
DEFINE_DECODER_SM83(DEC_HL,
info->mnemonic = SM83_MN_DEC;
info->op1.reg = SM83_REG_HL;
info->op1.flags = SM83_OP_FLAG_MEMORY;)
DEFINE_DECODER_SM83(SCF, info->mnemonic = SM83_MN_SCF)
DEFINE_DECODER_SM83(CCF, info->mnemonic = SM83_MN_CCF)
DEFINE_DECODER_SM83(CPL_, info->mnemonic = SM83_MN_CPL)
DEFINE_DECODER_SM83(DAA, info->mnemonic = SM83_MN_DAA)
#define DEFINE_POPPUSH_DECODER_SM83(REG) \
DEFINE_DECODER_SM83(POP ## REG, \
info->mnemonic = SM83_MN_POP; \
info->op1.reg = SM83_REG_ ## REG;) \
DEFINE_DECODER_SM83(PUSH ## REG, \
info->mnemonic = SM83_MN_PUSH; \
info->op1.reg = SM83_REG_ ## REG;) \
DEFINE_POPPUSH_DECODER_SM83(BC);
DEFINE_POPPUSH_DECODER_SM83(DE);
DEFINE_POPPUSH_DECODER_SM83(HL);
DEFINE_POPPUSH_DECODER_SM83(AF);
#define DEFINE_CB_OP_DECODER_SM83(NAME, BODY, OP) \
DEFINE_DECODER_SM83(NAME ## B, info->OP.reg = SM83_REG_B; BODY) \
DEFINE_DECODER_SM83(NAME ## C, info->OP.reg = SM83_REG_C; BODY) \
DEFINE_DECODER_SM83(NAME ## D, info->OP.reg = SM83_REG_D; BODY) \
DEFINE_DECODER_SM83(NAME ## E, info->OP.reg = SM83_REG_E; BODY) \
DEFINE_DECODER_SM83(NAME ## H, info->OP.reg = SM83_REG_H; BODY) \
DEFINE_DECODER_SM83(NAME ## L, info->OP.reg = SM83_REG_L; BODY) \
DEFINE_DECODER_SM83(NAME ## HL, info->OP.reg = SM83_REG_HL; info->OP.flags = SM83_OP_FLAG_MEMORY; BODY) \
DEFINE_DECODER_SM83(NAME ## A, info->OP.reg = SM83_REG_A; BODY)
#define DEFINE_CB_2_DECODER_SM83(NAME, BODY) \
DEFINE_CB_OP_DECODER_SM83(NAME, BODY, op2)
#define DEFINE_CB_1_DECODER_SM83(NAME, BODY) \
DEFINE_CB_OP_DECODER_SM83(NAME, BODY, op1)
#define DEFINE_CB_DECODER_SM83(NAME, BODY) \
DEFINE_CB_2_DECODER_SM83(NAME ## 0, info->op1.immediate = 0; BODY) \
DEFINE_CB_2_DECODER_SM83(NAME ## 1, info->op1.immediate = 1; BODY) \
DEFINE_CB_2_DECODER_SM83(NAME ## 2, info->op1.immediate = 2; BODY) \
DEFINE_CB_2_DECODER_SM83(NAME ## 3, info->op1.immediate = 3; BODY) \
DEFINE_CB_2_DECODER_SM83(NAME ## 4, info->op1.immediate = 4; BODY) \
DEFINE_CB_2_DECODER_SM83(NAME ## 5, info->op1.immediate = 5; BODY) \
DEFINE_CB_2_DECODER_SM83(NAME ## 6, info->op1.immediate = 6; BODY) \
DEFINE_CB_2_DECODER_SM83(NAME ## 7, info->op1.immediate = 7; BODY)
DEFINE_CB_DECODER_SM83(BIT, info->mnemonic = SM83_MN_BIT)
DEFINE_CB_DECODER_SM83(RES, info->mnemonic = SM83_MN_RES)
DEFINE_CB_DECODER_SM83(SET, info->mnemonic = SM83_MN_SET)
#define DEFINE_CB_X_DECODER_SM83(NAME) \
DEFINE_CB_1_DECODER_SM83(NAME, info->mnemonic = SM83_MN_ ## NAME) \
DEFINE_DECODER_SM83(NAME ## A_, info->mnemonic = SM83_MN_ ## NAME; \
info->op1.flags = SM83_OP_FLAG_IMPLICIT; \
info->op1.reg = SM83_REG_A;)
DEFINE_CB_X_DECODER_SM83(RL)
DEFINE_CB_X_DECODER_SM83(RLC)
DEFINE_CB_X_DECODER_SM83(RR)
DEFINE_CB_X_DECODER_SM83(RRC)
DEFINE_CB_1_DECODER_SM83(SLA, info->mnemonic = SM83_MN_SLA)
DEFINE_CB_1_DECODER_SM83(SRA, info->mnemonic = SM83_MN_SRA)
DEFINE_CB_1_DECODER_SM83(SRL, info->mnemonic = SM83_MN_SRL)
DEFINE_CB_1_DECODER_SM83(SWAP, info->mnemonic = SM83_MN_SWAP)
DEFINE_DECODER_SM83(DI, info->mnemonic = SM83_MN_DI)
DEFINE_DECODER_SM83(EI, info->mnemonic = SM83_MN_EI)
DEFINE_DECODER_SM83(HALT, info->mnemonic = SM83_MN_HALT)
DEFINE_DECODER_SM83(ILL, info->mnemonic = SM83_MN_ILL)
DEFINE_DECODER_SM83(STOP, info->mnemonic = SM83_MN_STOP)
#define DEFINE_RST_DECODER_SM83(VEC) \
DEFINE_DECODER_SM83(RST ## VEC, info->op1.immediate = 0x ## VEC;)
DEFINE_RST_DECODER_SM83(00);
DEFINE_RST_DECODER_SM83(08);
DEFINE_RST_DECODER_SM83(10);
DEFINE_RST_DECODER_SM83(18);
DEFINE_RST_DECODER_SM83(20);
DEFINE_RST_DECODER_SM83(28);
DEFINE_RST_DECODER_SM83(30);
DEFINE_RST_DECODER_SM83(38);
DEFINE_DECODER_SM83(CB, return 1)
const SM83Decoder _sm83DecoderTable[0x100] = {
DECLARE_SM83_EMITTER_BLOCK(_SM83Decode)
};
const SM83Decoder _sm83CBDecoderTable[0x100] = {
DECLARE_SM83_CB_EMITTER_BLOCK(_SM83Decode)
};
size_t SM83Decode(uint8_t opcode, struct SM83InstructionInfo* info) {
if (info->opcodeSize == sizeof(info->opcode)) {
return 0;
}
info->opcode[info->opcodeSize] = opcode;
SM83Decoder decoder;
switch (info->opcodeSize) {
case 0:
decoder = _sm83DecoderTable[opcode];
break;
case 1:
if (info->opcode[0] == 0xCB) {
decoder = _sm83CBDecoderTable[opcode];
break;
}
// Fall through
case 2:
++info->opcodeSize;
if (info->op1.reg) {
info->op2.immediate |= opcode << ((info->opcodeSize - 2) * 8);
} else {
info->op1.immediate |= opcode << ((info->opcodeSize - 2) * 8);
}
return 0;
default:
// Should never be reached
abort();
}
++info->opcodeSize;
return decoder(opcode, info);
}
#define ADVANCE(AMOUNT) \
if (AMOUNT >= blen) { \
buffer[blen - 1] = '\0'; \
return total; \
} \
total += AMOUNT; \
buffer += AMOUNT; \
blen -= AMOUNT;
static const char* _sm83Conditions[] = {
NULL,
"c",
"z",
"nc",
"nz",
};
static const char* _sm83Registers[] = {
"",
"b",
"c",
"d",
"e",
"h",
"l",
"a",
"f",
"bc",
"de",
"hl",
"af",
"sp",
"pc",
};
static const char* _sm83MnemonicStrings[] = {
"--",
"adc",
"add",
"and",
"bit",
"call",
"ccf",
"cp",
"cpl",
"daa",
"dec",
"di",
"ei",
"halt",
"inc",
"jp",
"jr",
"ld",
"nop",
"or",
"pop",
"push",
"res",
"ret",
"reti",
"rl",
"rlc",
"rr",
"rrc",
"rst",
"sbc",
"scf",
"set",
"sla",
"sra",
"srl",
"stop",
"sub",
"swap",
"xor",
"ill"
};
static int _decodeOperand(struct SM83Operand op, uint16_t pc, char* buffer, int blen) {
int total = 0;
if (op.flags & SM83_OP_FLAG_IMPLICIT) {
return 0;
}
strlcpy(buffer, " ", blen);
ADVANCE(1);
if (op.flags & SM83_OP_FLAG_MEMORY) {
strlcpy(buffer, "[", blen);
ADVANCE(1);
}
if (op.reg) {
int written = snprintf(buffer, blen, "%s", _sm83Registers[op.reg]);
ADVANCE(written);
} else {
int written;
if (op.flags & SM83_OP_FLAG_RELATIVE) {
written = snprintf(buffer, blen, "$%04X", pc + (int8_t) op.immediate);
} else {
written = snprintf(buffer, blen, "$%02X", op.immediate);
}
ADVANCE(written);
if (op.reg) {
strlcpy(buffer, "+", blen);
ADVANCE(1);
}
}
if (op.flags & SM83_OP_FLAG_INCREMENT) {
strlcpy(buffer, "+", blen);
ADVANCE(1);
}
if (op.flags & SM83_OP_FLAG_DECREMENT) {
strlcpy(buffer, "-", blen);
ADVANCE(1);
}
if (op.flags & SM83_OP_FLAG_MEMORY) {
strlcpy(buffer, "]", blen);
ADVANCE(1);
}
return total;
}
int SM83Disassemble(struct SM83InstructionInfo* info, uint16_t pc, char* buffer, int blen) {
const char* mnemonic = _sm83MnemonicStrings[info->mnemonic];
int written;
int total = 0;
const char* cond = _sm83Conditions[info->condition];
written = snprintf(buffer, blen, "%s", mnemonic);
ADVANCE(written);
if (cond) {
written = snprintf(buffer, blen, " %s", cond);
ADVANCE(written);
if (info->op1.reg || info->op1.immediate || info->op2.reg || info->op2.immediate) {
strlcpy(buffer, ",", blen);
ADVANCE(1);
}
}
if (info->op1.reg || info->op1.immediate || info->op2.reg || info->op2.immediate) {
written = _decodeOperand(info->op1, pc, buffer, blen);
ADVANCE(written);
}
if (info->op2.reg || (!info->op1.immediate && info->opcodeSize > 1 && info->opcode[0] != 0xCB)) {
if (written) {
strlcpy(buffer, ",", blen);
ADVANCE(1);
}
written = _decodeOperand(info->op2, pc, buffer, blen);
ADVANCE(written);
}
buffer[blen - 1] = '\0';
return total;
}