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old.cpp
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old.cpp
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#include <iostream>
#include <fstream>
#include <vector>
#include <cstring>
#include "common.h"
#include "regs.h"
#include "mr.h"
#include "rm.h"
#include "video.h"
#define VIRTUAL_MEMORY_SIZE (1024 * 720) // 720K of virtual memory for now
static uint8_t* virt_memory = NULL;
static uint16_t IP = 0;
static uint16_t regs[12]; // AX,BX,CX,DX SP,BP,SI,DI CS,DS,ES,SS
static int FLAG_ZERO = 0;
static int FLAG_INTERRUPT = 1;
static int FLAG_DIRECTION = 0;
static int FLAG_CARRY = 0;
static int SEGREG_OVERRIDE = -1;
static int running = 1; // if the CPU is running, i.e executing instructions
static std::string printed = std::string();
uint8_t * getmemory() { return virt_memory; }
uint16_t getregval(uint8_t regid);
void setregval(uint8_t regid, uint16_t val);
void interrupt(uint8_t intid) {
if (!FLAG_INTERRUPT)
return;
if (intid == 0x10) { // BIOS display services
if (getregval(REGISTER_AH) == 0x0E) {
printed.push_back(getregval(REGISTER_AL));
printf("VM BIOS print char: %c [vbuf=%s]\n", getregval(REGISTER_AL), printed.c_str());
} else if (getregval(REGISTER_AH) == 0) {
printf("VM change video mode to %d\n",getregval(REGISTER_AL));
switch (getregval(REGISTER_AL)) {
case 0x13:
initvideo(320,200,0xA000);
break;
default:
printf("WARNING: Unimplemented video mode %d\n",getregval(REGISTER_AH));
}
}
} else if (intid == 0xFF) { // 0:0 jump callback
printf("0000:0000 has been jumped to. Halting.\n");
} else if (intid == 0xFE) { // sooper secret prints for in-VM things like the boot ROM
printf("VM: %s\n", virt_memory + getregval(REGISTER_SI));
setregval(REGISTER_SI, 0);
} else if (intid == 0x1A) {
setregval(REGISTER_DX, 0);
}
}
void setregval(uint8_t regid, uint16_t val) {
if (regid < 4) {
//printf("SET LOW REG %s[%s] TO %x\n",getregname(regid), getregname(regid+8), val&0x00FF);
regs[regid] &= 0xFF00;
regs[regid] |= val & 0x00FF;
} else if (regid < 8) {
//printf("SET HIGH REG %s[%s] TO %02x\n",getregname(regid), getregname(regid+4), (val&0xFF));
regs[regid - 4] &= 0x00FF;
regs[regid - 4] |= (val & 0xFF) << 8;
} else {
//printf("SET REG %s[%d] TO %x\n",getregname(regid), regid - 8, val);
regs[regid - 8] = val;
}
}
uint16_t getregval(uint8_t regid) {
if (regid < 4) {
return regs[regid] & 0xFF;
} else if (regid < 8) {
return (regs[regid - 4] & 0xFF00) >> 8;
} else {
return regs[regid - 8];
}
}
void regdump() {
printf("[");
for (int i=0;i<0x8;i++) {
printf("%s=0x%04X ", getregname(i + 8), getregval(i + 8));
}
printf("IP=0x%04X CS=%X DS=%X ES=%X SS=%X] ",IP,
getregval(REGISTER_CS), getregval(REGISTER_DS), getregval(REGISTER_ES), getregval(REGISTER_SS));
}
void loadsector(uint16_t sid, uint16_t destination, uint16_t count, const char* file) {
std::ifstream input( file, std::ios::binary );
std::vector<unsigned char> buffer(std::istreambuf_iterator<char>(input), {});
if (buffer.size() / 512 < count || buffer.size() < (sid*512 + count*512)) {
fprintf(stderr, "Warning: file %s doesn't contain enough data to read %d sectors (fz=%d, rq=%d). Aborting.\n", file, count, buffer.size(), (sid*512 + count*512));
input.close();
return;
}
memcpy(virt_memory + destination, buffer.data() + (sid*512), count * 512);
printf("Loaded %d sectors from %s [sector %d] to 0x%X\n", count, file, sid, destination);
}
void jump(uint16_t addr) {
IP = addr;
}
uint32_t segcalc(uint16_t seg, uint16_t off) {
uint32_t ret = seg;
ret = ret << 4;
ret += off;
return ret;
}
uint32_t pushw(uint16_t val) {
uint32_t stackptr = segcalc(getregval(REGISTER_SS), getregval(REGISTER_SP));
setregval(REGISTER_SP, getregval(REGISTER_SP) - 2);
*((uint16_t*)virt_memory+stackptr) = val;
return stackptr;
}
uint16_t popw() {
setregval(REGISTER_SP, getregval(REGISTER_SP) + 2);
uint32_t stackptr = segcalc(getregval(REGISTER_SS), getregval(REGISTER_SP));
return *((uint16_t*)virt_memory+stackptr);
}
// this is a lazy, likely buggy 8086 emulator.
// i will probably rewrite this in the future
int main() {
printf("Starting charlie86\n");
printf("Registers: [");
for (int i=0;i<0xF;i++) {
regs[i] = 0;
printf("%s=%X ", getregname(i), regs[i]);
}
printf("IP=%X]\n",IP);
virt_memory = (unsigned char*) malloc(VIRTUAL_MEMORY_SIZE);
memset(virt_memory, 0, VIRTUAL_MEMORY_SIZE);
memset(virt_memory + 0xA000, 40, 320*240);
printf("Allocated %d bytes of virtual memory\n", VIRTUAL_MEMORY_SIZE);
printf("Loading bootsector..\n");
//loadsector(0, 0x7C00,1, "../disk/INVADERS.BIN");
loadsector(0, 0x7C00, 1, "../disk/BOOTSEC.BIN");
loadsector(0, 0x500, 1, "../disk/BOOTROM.BIN"); // load the ROM/(BIOS i guess) at 0x500
jump(0x500);
// This is now handled in-VM (in the ROM)
//if (virt_memory[0x7DFE] != 0x55 || virt_memory[0x7DFF] != 0xAA) {
// fprintf(stderr, "Warning: Magic number 55AA not present in bootsector! [%x%x]\n", virt_memory[0x7DFE], virt_memory[0x7DFF]);
//}
while (running) {
uint8_t ipc = *(virt_memory+IP);
IP++;
int rec = false;
if ((ipc & (uint8_t)0xF0) == 0xB0) { // MOV *mostly*
rec = true;
uint8_t regid = ipc & (uint8_t)0xF;
char* regname = (char*) getregname(regid);
uint16_t d = 0;
int wide = 1;
if (regid >= 8){
d = (virt_memory[IP]) + (virt_memory[IP+1] << (uint8_t)8);
IP+=2;
} else {
d = virt_memory[IP];
IP++;
wide = 0;
}
setregval(regid, d);
regdump();
if (wide)
printf("MOV %s, 0x%04x [wide]\n",regname,d);
else
printf("MOV %s, 0x%02x\n",regname,d);
} else if ((ipc & 0xF0) == 0xA0 && (ipc & 0x0F) < 3) { // MOV A(L/X)
rec = true;
uint8_t regid = (ipc & 0x0F) << 3; // either reg 0 (al) or reg 8 (ax)
uint16_t a = (virt_memory[IP]) + (virt_memory[IP+1] << (uint8_t)8);
IP+=2;
uint16_t d = 0;
int wide = 1;
if (regid >= 8){
d = (virt_memory[a+1]) + (virt_memory[a] << (uint8_t)8);
} else {
d = virt_memory[a];
wide = 0;
}
setregval(regid, d);
regdump();
if (wide)
printf("MOV %s, [0x%04x] [wide]\n",getregname(regid),a);
else
printf("MOV %s, [0x%04x]\n",getregname(regid),a);
} else if (ipc == 0x8C || ipc == 0x8E) { // MOV sr, mrw and vice versa
rec = true;
uint8_t mr = virt_memory[IP];
IP++;
uint8_t mod = (mr & 0b11000000) >> 6;
uint8_t reg = (mr & 0b00111000) >> 3;
uint8_t rm = (mr & 0b00000111);
uint8_t w = 1;
uint8_t d = (ipc & 0b10) >> 1;
uint8_t regid1, regid2;
if (!d) {
regid1 = (reg + (w << 3));
regid2 = sr2regid(rm);
} else {
regid1 = (rm + (w << 3));
regid2 = sr2regid(reg);
}
uint16_t loc;
switch (mod) {
case MR_RM1:
loc = rm2loc(rm);
*(virt_memory + loc) = (uint16_t)getregval(regid1);
regdump();
printf("MOV %s, %s\n", getrmname(rm), getregname(regid1));
break;
case MR_RM2_DISP8:
case MR_RM2_DISP16:
printf("FIXME: Unimplemented MOV memory access mode %d\n",mod);
running = false;
break;
case MR_2REG:
setregval(regid2, getregval(regid1));
if (getregval(regid2) == 0)
FLAG_ZERO = 1;
regdump();
printf("MOV %s, %s\n", getregname(regid2), getregname(regid1));
}
} else if (ipc == 0x89 || ipc == 0x8B) { // MOV WORD rw, mrw and vice versa
rec = true;
uint8_t mr = virt_memory[IP];
IP++;
uint8_t mod = (mr & 0b11000000) >> 6;
uint8_t reg = (mr & 0b00111000) >> 3;
uint8_t rm = (mr & 0b00000111);
uint8_t w = 1;
uint8_t d = (ipc & 0b10) >> 1;
uint8_t regid1, regid2;
regid1 = (reg + (w << 3));
regid2 = (rm + (w << 3));
uint16_t loc;
sint8_t l1;
sint16_t l2;
switch (mod) {
case MR_RM1:
loc = rm2loc(rm);
if (!d) {
*(virt_memory + loc) = getregval(regid1);
regdump();
printf("MOV %s, %s\n", getrmname(rm), getregname(regid1));
} else {
setregval(regid1, (uint16_t) *(virt_memory + loc));
regdump();
printf("MOV %s, %s\n", getregname(regid1), getrmname(rm));
}
break;
case MR_RM2_DISP8:
l1 = (sint8_t)(virt_memory[IP]);
IP++;
*(virt_memory + getrmdispval(rm, l1)) = getregval(regid1);
regdump();
printf("MOV [%s%s%d], %s\n", getrmnamenb(rm), (l1<0)?"":"+",l1, getregname(regid1));
break;
case MR_RM2_DISP16:
l2 = (sint16_t)(virt_memory[IP] + (virt_memory[IP+1]<<8));
IP+=2;
*(virt_memory + getrmdispval(rm, l2)) = getregval(regid1);
regdump();
printf("MOV [%s%s%d], %s\n", getrmnamenb(rm), (l2<0)?"":"+",l2, getregname(regid1));
break;
case MR_2REG:
setregval(regid2, getregval(regid1));
if (getregval(regid2) == 0)
FLAG_ZERO = 1;
regdump();
printf("MOV %s, %s\n", getregname(regid2), getregname(regid1));
}
} else if (ipc == 0x88 || ipc == 0x8A) { // MOV BYTE rw, mrw and vice versa
rec = true;
uint8_t mr = virt_memory[IP];
IP++;
uint8_t mod = (mr & 0b11000000) >> 6;
uint8_t reg = (mr & 0b00111000) >> 3;
uint8_t rm = (mr & 0b00000111);
uint8_t w = 0;
uint8_t d = (ipc & 0b10) >> 1;
uint8_t regid1, regid2;
regid1 = (reg + (w << 3));
regid2 = (rm + (w << 3));
uint16_t loc;
switch (mod) {
case MR_RM1:
loc = rm2loc(rm);
if (!d) {
*(virt_memory + loc) = getregval(regid1);
regdump();
printf("MOV %s, %s\n", getrmname(rm), getregname(regid1));
} else {
setregval(regid1, (uint16_t) *(virt_memory + loc));
regdump();
printf("MOV %s, %s\n", getregname(regid1), getrmname(rm));
}
break;
case MR_RM2_DISP8:
case MR_RM2_DISP16:
printf("FIXME: Unimplemented MOV memory access mode %d\n",mod);
running = false;
break;
case MR_2REG:
setregval(regid2, getregval(regid1));
if (getregval(regid2) == 0)
FLAG_ZERO = 1;
regdump();
printf("MOV %s, %s\n", getregname(regid2), getregname(regid1));
}
} else if (ipc == 0xA2 || ipc == 0xA3) { // MOV [x], AL
rec=1;
uint8_t regid = REGISTER_AL + (ipc==0xA3?8:0);
uint16_t dest = virt_memory[IP] + (virt_memory[IP+1]<<8);
IP+=2;
if (ipc==0xA3) {
*(virt_memory+dest) = getregval(REGISTER_AX);
} else {
virt_memory[dest] = getregval(REGISTER_AL)&0xFF;
}
regdump();
printf("MOV [0x%X], %s\n",dest, getregname(regid));
} else if (ipc == 0xC7) { // mov word [reg], val
rec=1;
uint8_t mr = virt_memory[IP];
IP++;
uint8_t mod = (mr & 0b11000000) >> 6;
uint8_t reg = (mr & 0b00111000) >> 3;
uint8_t rm = (mr & 0b00000111);
uint8_t w = 0;
uint8_t d = (ipc & 0b10) >> 1;
switch (mod) {
case MR_RM1:
if (rm == RM_DIRECT) {
uint16_t dest = virt_memory[IP] + (virt_memory[IP+1]<<8);
IP+=2;
uint16_t term = virt_memory[IP] + (virt_memory[IP+1]<<8);
IP+=2;
*(virt_memory + dest) = term;
regdump();
printf("MOV [0x%X], %X\n",dest,term);
break;
} else {
uint16_t loc = rm2loc(rm);
uint16_t term = virt_memory[IP] + (virt_memory[IP+1]<<8);
*(virt_memory + loc) = virt_memory[IP];
*(virt_memory + loc + 1) = virt_memory[IP+1];
IP+=2;
regdump();
printf("MOV %s, %X\n",getrmname(rm),term);
break;
}
case MR_RM2_DISP8:
case MR_RM2_DISP16:
case MR_2REG:
printf("FIXME: [C7] Unimplemented MOV memory access mode %d\n",mod);
running = false;
break;
}
}
if (ipc == 0x3C || ipc == 0x3D) { // CMP A(L/X)
rec = true;
uint8_t regid = (ipc == 0x3D) << 3; // either reg 0 (al) or reg 8 (ax)
uint16_t d = 0;
int wide = 1;
if (regid >= 8){
d = (virt_memory[IP]) + (virt_memory[IP+1] << (uint8_t)8);
IP+=2;
} else {
d = virt_memory[IP];
IP++;
wide = 0;
}
FLAG_ZERO = getregval(regid) == d;
regdump();
if (wide)
printf("CMP %s, 0x%04x [wide]\n",getregname(regid),d);
else
printf("CMP %s, 0x%02x\n",getregname(regid),d);
} else if ((ipc == 0x80 || ipc == 0x83) && ((virt_memory[IP])&0b111000)==0b111000) { // CMP rm[w/b] ib
rec = true;
uint8_t mr = virt_memory[IP];
IP++;
uint8_t mod = (mr & 0b11000000) >> 6;
uint8_t reg = (mr & 0b00111000) >> 3;
uint8_t rm = (mr & 0b00000111);
uint8_t w = ipc & 1;
uint8_t wi = (ipc == 0x81);
uint8_t regid1 = reg + (w<<3);
uint8_t regid2 = rm + (w<<3);
uint16_t loc;
uint16_t op1 = 0xFFFF;
uint16_t op2 = 0xFFFE;
switch (mod) {
case MR_RM1:
loc = rm2loc(rm);
op1 = (uint16_t)*(virt_memory + loc);
if (w) {
op2 = ((virt_memory[IP] << 8) + virt_memory[IP]);
IP+=2;
} else {
op2 = virt_memory[IP];
IP++;
}
regdump();
printf("CMP %s, 0x%X\n",getrmname(rm), op2);
break;
case MR_RM2_DISP8:
case MR_RM2_DISP16:
printf("FIXME: [80,83] Unimplemented CMP memory access mode %d\n",mod);
running = false;
break;
case MR_2REG:
op2 = getregval(regid1);
op1 = getregval(regid2);
if (op1 == op2)
FLAG_ZERO = 1;
regdump();
printf("CMP %s, %s\n", getregname(regid1), getregname(regid2));
break;
}
} else if (ipc == 0x81 && ((virt_memory[IP])&0b111000)==0b111000) { // CMP word REG, VAL
rec=true;
uint8_t mr = virt_memory[IP];
IP++;
uint8_t mod = (mr & 0b11000000) >> 6;
uint8_t reg = (mr & 0b00111000) >> 3;
uint8_t rm = (mr & 0b00000111);
uint8_t w = ipc & 1;
uint8_t wi = (ipc == 0x81);
uint8_t regid1 = rm + (w<<3);
uint16_t val = ((virt_memory[IP+1] << 8) + virt_memory[IP]);
IP+=2;
regdump();
printf("CMP %s, 0x%X\n", getregname(regid1), val);
}
if (ipc == 0xAC) { // LODSB
rec = true;
setregval(REGISTER_AL, *(virt_memory + getregval(REGISTER_SI)));
if (FLAG_DIRECTION)
setregval(REGISTER_SI, getregval(REGISTER_SI) - 1);
else
setregval(REGISTER_SI, getregval(REGISTER_SI) + 1);
regdump();
printf("LODSB\n");
} else if (ipc == 0xAD) { // LODSW
rec = true;
setregval(REGISTER_AX, *(virt_memory + getregval(REGISTER_SI)));
if (FLAG_DIRECTION)
setregval(REGISTER_SI, getregval(REGISTER_SI) - 1);
else
setregval(REGISTER_SI, getregval(REGISTER_SI) + 1);
regdump();
printf("LODSW\n");
}
if (ipc == 0x08 || ipc == 0x09) { // OR
rec = true;
uint8_t mr = virt_memory[IP];
IP++;
uint8_t mod = (mr & 0b11000000) >> 6;
uint8_t reg = (mr & 0b00111000) >> 3;
uint8_t rm = (mr & 0b00000111);
uint8_t w = ipc & 1;
uint8_t regid = -1;
switch (mod) {
case MR_RM1:
case MR_RM2_DISP8:
case MR_RM2_DISP16:
printf("FIXME: Unimplemented OR memory access mode\n");
rec = false; // let's just ignore this for now :)
continue;
case MR_2REG:
regid = reg + (w<<3);
setregval(regid, getregval(regid) | getregval(regid));
if (getregval(regid) == 0)
FLAG_ZERO = 1;
default:
rec = false; // can't happen so probably a good idea to raise an error
continue;
}
regdump();
printf("OR mod=%x, reg=%s, rm=%x\n", mod, getregname(regid), rm);
}
if (ipc == 0x00 || ipc == 0x01) { // ADD
rec = true;
uint8_t mr = virt_memory[IP];
IP++;
uint8_t mod = (mr & 0b11000000) >> 6;
uint8_t reg = (mr & 0b00111000) >> 3;
uint8_t rm = (mr & 0b00000111);
uint8_t w = ipc & 1;
uint8_t regid1 = reg + (w<<3);
uint8_t regid2 = rm + (w<<3);
uint16_t loc;
switch (mod) {
case MR_RM1:
loc = rm2loc(rm);
*(virt_memory + loc) = getregval(regid1) + (uint16_t)*(virt_memory + loc);
regdump();
printf("ADD %s, %s\n", getrmname(rm), getregname(regid1));
break;
case MR_RM2_DISP8:
case MR_RM2_DISP16:
printf("FIXME: Unimplemented ADD memory access mode %d\n",mod);
running = false;
break;
case MR_2REG:
setregval(regid2, getregval(regid1) + getregval(regid2));
if (getregval(regid2) == 0)
FLAG_ZERO = 1;
regdump();
printf("ADD %s, %s\n", getregname(regid2), getregname(regid1));
}
} else if ((ipc == 0x80 || ipc == 0x83) && ((virt_memory[IP])&0b111000)==0) { // ADD rmw, ib
rec = true;
uint8_t mr = virt_memory[IP];
IP++;
uint8_t il = (mr & 0b11000000) >> 6;
uint8_t reg = (mr & 0b00111000) >> 3;
uint8_t rm = (mr & 0b00000111);
uint8_t w = ipc & 1;
uint8_t regid2 = rm + (w<<3);
uint16_t loc;
uint16_t amt = 0;
switch (il) {
case 3:
amt += virt_memory[IP];
IP++;
break;
case 4:
amt += (virt_memory[IP]<<8) + virt_memory[IP];
IP+=2;
break;
case 5:
printf("FIXME: Unimplemented ADD IL mode\n");
running = false;
break;
}
setregval(regid2, amt + getregval(regid2));
if (getregval(regid2) == 0)
FLAG_ZERO = 1;
regdump();
printf("ADD %s, %d\n", getregname(regid2), amt);
} else if (ipc == 0x04 || ipc == 0x05) {
uint8_t wide = ipc&1;
uint16_t v;
if (wide) {
v = (virt_memory[IP+1]<<8) + virt_memory[IP];
IP+=2;
setregval(REGISTER_AX, getregval(REGISTER_AX) + v);
} else {
v = virt_memory[IP];
setregval(REGISTER_AL, getregval(REGISTER_AL) + v);
IP++;
}
regdump();
printf("ADD %s, 0x%04X\n", getregname(REGISTER_AL + (wide<<3)), v);
rec = true;
}
if (ipc == 0x30 || ipc == 0x31) { // XOR
rec = true;
uint8_t mr = virt_memory[IP];
IP++;
uint8_t mod = (mr & 0b11000000) >> 6;
uint8_t reg = (mr & 0b00111000) >> 3;
uint8_t rm = (mr & 0b00000111);
uint8_t w = ipc & 1;
uint8_t regid1 = reg + (w<<3);
uint8_t regid2 = rm + (w<<3);
uint16_t loc;
switch (mod) {
case MR_RM1:
loc = rm2loc(rm);
*(virt_memory + loc) = getregval(regid1) ^ (uint16_t)*(virt_memory + loc);
regdump();
printf("XOR %s, %s\n", getrmname(rm), getregname(regid1));
break;
case MR_RM2_DISP8:
case MR_RM2_DISP16:
printf("FIXME: Unimplemented OR memory access mode %d\n",mod);
running = false;
break;
case MR_2REG:
setregval(regid2, getregval(regid1) ^ getregval(regid2));
if (getregval(regid2) == 0)
FLAG_ZERO = 1;
regdump();
printf("XOR %s, %s\n", getregname(regid2), getregname(regid1));
}
}
if (ipc == 0x74) { // JZ
rec=true;
sint8_t rel = (sint8_t)virt_memory[IP];
IP++;
if (FLAG_ZERO)
jump(IP + rel);
int jumped = FLAG_ZERO;
FLAG_ZERO = 0;
regdump();
printf("JZ 0x%04X",IP);
if (jumped)
printf(" [jumped]");
else
printf(" [not jumped]");
printf("\n");
} else if (ipc == 0x75) { // JNZ
rec=true;
sint8_t rel = (sint8_t)virt_memory[IP];
IP++;
if (!FLAG_ZERO)
jump(IP + rel);
int jumped = !FLAG_ZERO;
regdump();
printf("JNZ 0x%04X",IP);
if (jumped)
printf(" [jumped]");
else
printf(" [not jumped]");
printf("\n");
}
if (ipc == 0xCC || ipc == 0xCD) { // INT
rec=true;
uint8_t intid = 0xFF;
if (ipc==0xCC) {
intid = 3;
} else {
intid = virt_memory[IP];
IP++;
}
regdump();
printf("INT 0x%02X\n",intid);
interrupt(intid);
}
if (ipc == 0xEB) { // JUMP SHORT 8
rec = true;
sint8_t rel = (sint8_t)virt_memory[IP];
IP++;
jump(IP + rel);
regdump();
printf("JMP 0x%04X [near, 8, %02X]\n",IP, rel);
}
if (ipc == 0xE9) { // JUMP SHORT 16
rec = true;
sint16_t rel = (sint16_t)(virt_memory[IP] + (virt_memory[IP+1] << 8));
IP+=2;
int neg = rel<0;
if (rel < 0 && (rel+IP) < 0)
jump(0xFFFF - rel);
else
jump(IP + rel);
regdump();
printf("JMP 0x%04X [near, 16, %c%04X]\n",IP, neg?'-':'+', (uint16_t)rel);
}
if (ipc == 0xEA) { // JUMP FAR
rec = true;
uint16_t off = (virt_memory[IP] + (virt_memory[IP + 1] << 8));
IP+=2;
uint16_t seg = virt_memory[IP] + (virt_memory[IP + 1] << 8);
setregval(REGISTER_CS, seg);
IP+=2;
jump(off);
regdump();
printf("JMP 0x%04X [far, 16, %04X:%04X]\n",IP, seg, off);
}
if (ipc == 0xFA) { // CLI
regdump();
printf("CLI\n");
rec = true;
FLAG_INTERRUPT = 0;
}
if (ipc == 0xF4) { // HLT
regdump();
printf("HLT\n");
rec = true;
running = false;
break;
}
if (ipc == 0x90) { // NOP
regdump();
printf("NOP\n");
rec = true;
}
if (ipc == 0xFC) { // CLD
regdump();
printf("CLD\n");
FLAG_DIRECTION = 0;
rec = true;
}
if (ipc == 0xF3) { // REP
uint8_t next = virt_memory[IP];
IP++;
uint8_t wide;
uint8_t d;
uint32_t start;
int reps = 0;
if (next==0xAA || next==0xAB)
start = segcalc(getregval(REGISTER_ES),getregval(REGISTER_DI));
while (getregval(REGISTER_CX) > 0) {
reps++;
switch (next) {
case 0xAA:
case 0xAB: // REP STOS[B/W]
wide = next & 1;
d = (next & 0b10) >> 1;
if (wide) {
(*(virt_memory + segcalc(getregval(REGISTER_ES),getregval(REGISTER_DI)))) = getregval(REGISTER_AX);
} else {
(*(virt_memory + segcalc(getregval(REGISTER_ES),getregval(REGISTER_DI)))) = (uint8_t) getregval(REGISTER_AL);
}
if (d) {
setregval(REGISTER_DI, getregval(REGISTER_DI + wide + 1));
} else {
setregval(REGISTER_DI, getregval(REGISTER_DI - (wide + 1)));
}
break;
default:
printf("FIXME: Not implemented REP operation %02X\n", next);
rec = false;
break;
}
setregval(REGISTER_CX, getregval(REGISTER_CX) - 1);
}
if (next == 0xAA || next == 0xAB) {
regdump();
printf("REP STOS [%d(%X) reps, %X start, %X end]\n",reps,reps,start,segcalc(getregval(REGISTER_ES),getregval(REGISTER_DI)));
} else {
regdump();
printf("REP (unk) [%d(%X) reps]\n",reps,reps);
}
rec = true;
}
if (ipc >= 0x40 && ipc <= 0x47) { // INC [reg]
uint8_t regid = inc2regid(ipc - 0x40);
setregval(regid, getregval(regid) + 1);
regdump();
printf("INC %s\n", getregname(regid));
rec = true;
} else if (ipc == 0xFE || ipc == 0xFF) {
uint8_t mr = virt_memory[IP];
IP++;
uint8_t mod = (mr & 0b11000000) >> 6;
uint8_t reg = (mr & 0b00111000) >> 3;
uint8_t rm = (mr & 0b00000111);
uint8_t w = ipc & 1;
uint8_t regid1 = reg + (w<<3);
uint8_t regid2 = rm + (w<<3);
setregval(regid2, getregval(regid2)+1);
regdump();
printf("INC %s\n",getregname(regid2));
rec=true;
}
if (ipc == 0xAA || ipc == 0xAB) { // STOS[B/W]
uint8_t wide = ipc & 1;
uint8_t d = (ipc & 0b10) >> 1;
if (wide) {
(*(virt_memory + segcalc(getregval(REGISTER_ES),getregval(REGISTER_DI)))) = getregval(REGISTER_AX);
} else {
(*(virt_memory + segcalc(getregval(REGISTER_ES),getregval(REGISTER_DI)))) = (uint8_t) getregval(REGISTER_AL);
}
uint16_t bdi = getregval(REGISTER_DI);
if (!d) {
setregval(REGISTER_DI, getregval(REGISTER_DI) + (wide + 1));
} else {
setregval(REGISTER_DI, getregval(REGISTER_DI) - (wide + 1));
}
rec = true;
regdump();
printf("STOSW %04X => %X\n",getregval(REGISTER_AX),segcalc(getregval(REGISTER_ES),bdi));
}
if (ipc >= 0x91 && ipc <= 0x97) { // XCHG AX,[reg]
uint8_t regid = inc2regid(ipc - 0x90);
uint16_t ro = getregval(REGISTER_AX);
setregval(REGISTER_AX, getregval(regid));
setregval(regid, ro);
regdump();
printf("XCHG AX,%s\n", getregname(regid));
rec = true;
}
if (ipc == 0xE2) { // LOOP
sint8_t dest = (sint8_t)virt_memory[IP];
IP++;
uint8_t jumped = 0;
if (getregval(REGISTER_CX) > 0) {
setregval(REGISTER_CX, getregval(REGISTER_CX) - 1);
jump(IP + dest);
jumped = 1;
}
regdump();
printf("LOOP %04X [%s]\n",IP,jumped?"jumped":"not jumped");
rec = true;
}
if (ipc >= 0x50 && ipc <= 0x57) { // PUSH
rec=true;
uint8_t regid = (ipc-0x50) + 8;
pushw(getregval(regid));
regdump();
printf("PUSH %s\n", getregname(regid));
}
if (ipc >= 0x58 && ipc <= 0x5F) { // POP
rec=true;
uint8_t regid = (ipc-0x58) + 8;
setregval(regid, popw());
regdump();