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#include "disasm.h"
#include "data_buffer.h"
#include "common.h"
#include <cstdio>
static size_t disasm_verbatim(
char *out, size_t out_sz, size_t *instr_sz, uint16_t instr, uint32_t, const DataBuffer &)
{
if (instr_sz) {
*instr_sz = kInstructionSizeStepBytes;
}
return Min(out_sz, snprintf(out, out_sz, " .short 0x%04x", instr));
}
static size_t disasm_mfff0_v4e70(
char *out, size_t out_sz, size_t *instr_sz, uint16_t instr, uint32_t offset, const DataBuffer &code)
{
if (instr_sz) {
*instr_sz = kInstructionSizeStepBytes;
}
if (instr == 0x4e70) {
return Min(out_sz, snprintf(out, out_sz, " reset"));
} else if (instr == 0x4e71) {
return Min(out_sz, snprintf(out, out_sz, " nop"));
} else if (instr == 0x4e73) {
return Min(out_sz, snprintf(out, out_sz, " rte"));
} else if (instr == 0x4e75) {
return Min(out_sz, snprintf(out, out_sz, " rts"));
} else if (instr == 0x4e76) {
return Min(out_sz, snprintf(out, out_sz, " trapv"));
} else if (instr == 0x4e77) {
return Min(out_sz, snprintf(out, out_sz, " rtr"));
}
return disasm_verbatim(out, out_sz, instr_sz, instr, offset, code);
}
enum class JsrJmp {
kJsr,
kJmp,
};
static size_t disasm_jsr_jmp(
char *out, size_t out_sz, size_t *instr_sz, uint16_t instr, uint32_t offset, const DataBuffer & code, JsrJmp jsrjmp)
{
const char *instr_repr = (jsrjmp == JsrJmp::kJsr) ? "jsr" : "jmp";
const int addrmode = instr & 0x3f;
const int m = (addrmode >> 3) & 0x7;
const int xn = addrmode & 0x7;
switch (m) {
case 0: // 4e80 .. 4e87
case 1: // 4e88 .. 4e8f
break;
case 2: // 4e90 .. 4e97
if (instr_sz) {
*instr_sz = kInstructionSizeStepBytes;
}
return Min(out_sz, snprintf(out, out_sz, " %s %%a%d@", instr_repr, xn));
case 3: // 4e98 .. 4e9f
case 4: // 4ea0 .. 4ea7
break;
case 5: // 4ea8 .. 4eaf, Displacement
{
if (instr_sz) {
*instr_sz = kInstructionSizeStepBytes * 2;
}
const int16_t dispmt = GetI16BE(code.buffer + offset + kInstructionSizeStepBytes);
return Min(out_sz, snprintf(out, out_sz, " %s %%a%d@(%d:w)", instr_repr, xn, dispmt));
}
case 6: // 4eb0 .. 4eb7, Brief Extension Word
{
if (instr_sz) {
*instr_sz = kInstructionSizeStepBytes * 2;
}
const uint16_t briefext = GetU16BE(code.buffer + offset + kInstructionSizeStepBytes);
const char reg = ((briefext >> 15) & 1) ? 'a' : 'd';
const int xn2 = (briefext >> 12) & 7;
const char size_spec = ((briefext >> 11) & 1) ? 'l' : 'w';
const int8_t dispmt = briefext & 0xff;
return Min(out_sz, snprintf(
out, out_sz, " %s %%a%d@(%d,%%%c%d:%c)",
instr_repr, xn, dispmt, reg, xn2, size_spec));
}
case 7: // 4eb8 .. 4ebf, some are with Brief Extension Word
switch (xn) {
case 0: // 4eb8 (xxx).W
{
if (instr_sz) {
*instr_sz = kInstructionSizeStepBytes * 2;
}
const int32_t dispmt = GetI16BE(code.buffer + offset + kInstructionSizeStepBytes);
return Min(out_sz, snprintf(out, out_sz, " %s 0x%x:w", instr_repr, dispmt));
}
case 1: // 4eb9 (xxx).L
{
if (instr_sz) {
*instr_sz = kInstructionSizeStepBytes * 3;
}
const int32_t dispmt = GetI32BE(code.buffer + offset + kInstructionSizeStepBytes);
return Min(out_sz, snprintf(out, out_sz, " %s 0x%x:l", instr_repr, dispmt));
}
case 2: // 4eba, Displacement
{
if (instr_sz) {
*instr_sz = kInstructionSizeStepBytes * 2;
}
const int16_t dispmt = GetI16BE(code.buffer + offset + kInstructionSizeStepBytes);
return Min(out_sz, snprintf(out, out_sz, " %s %%pc@(%d:w)", instr_repr, dispmt));
}
case 3: // 4ebb
{
if (instr_sz) {
*instr_sz = kInstructionSizeStepBytes * 2;
}
const uint16_t briefext = GetU16BE(
code.buffer + offset + kInstructionSizeStepBytes);
const char reg = ((briefext >> 15) & 1) ? 'a' : 'd';
const int xn2 = (briefext >> 12) & 7;
const char size_spec = ((briefext >> 11) & 1) ? 'l' : 'w';
const int8_t dispmt = briefext & 0xff;
return Min(out_sz, snprintf(
out, out_sz, " %s %%pc@(%d,%%%c%d:%c)", instr_repr, dispmt, reg, xn2, size_spec));
}
case 4: // 4ebc
case 5: // 4ebd
case 6: // 4ebe
break;
}
break;
}
return disasm_verbatim(out, out_sz, instr_sz, instr, offset, code);
}
size_t m68k_disasm(
char *out, size_t out_sz, size_t *instr_sz, uint16_t instr, uint32_t offset, const DataBuffer &code)
{
if ((instr & 0xfff0) == 0x4e70) {
return disasm_mfff0_v4e70(out, out_sz, instr_sz, instr, offset, code);
} else if ((instr & 0xffc0) == 0x4e80) {
return disasm_jsr_jmp(out, out_sz, instr_sz, instr, offset, code, JsrJmp::kJsr);
} else if ((instr & 0xffc0) == 0x4ec0) {
return disasm_jsr_jmp(out, out_sz, instr_sz, instr, offset, code, JsrJmp::kJmp);
}
return disasm_verbatim(out, out_sz, instr_sz, instr, offset, code);
}
size_t m68k_render_raw_data_comment(
char *out, size_t out_sz, uint32_t offset, size_t instr_sz, const DataBuffer &code)
{
size_t overall_sz = Min(out_sz, snprintf(out, out_sz, " |"));
for (size_t i = 0; i < instr_sz; i += kInstructionSizeStepBytes)
{
overall_sz += Min(
out_sz - overall_sz,
snprintf(
out + overall_sz,
out_sz - overall_sz,
" %04x",
GetU16BE(code.buffer + offset + i)));
}
overall_sz += Min(
out_sz - overall_sz,
snprintf(out + overall_sz, out_sz - overall_sz, " @%08x", offset));
return overall_sz;
}
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