Apple-2-Tools/bradgrantham-apple2e
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This commit is contained in:
Brad Grantham 2016-11-06 15:41:18 -08:00
parent cd7dd66e5e
commit 65ef5c3b8d
1 changed files with 132 additions and 9 deletions
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141
apple2e.cpp
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@ -392,6 +392,14 @@ struct CPU6502
break;
}
case 0xBA: {
if(debug & DEBUG_DECODE) printf("TSX\n");
x = s;
flag_change(Z, x == 0x00);
flag_change(N, x & 0x80);
break;
}
case 0x9A: {
if(debug & DEBUG_DECODE) printf("TXS\n");
s = x;
@ -484,8 +492,16 @@ struct CPU6502
break;
}
case 0xE8: {
if(debug & DEBUG_DECODE) printf("INX\n");
x = x + 1;
flag_change(Z, x == 0x00);
flag_change(N, x & 0x80);
break;
}
case 0xC8: {
if(debug & DEBUG_DECODE) printf("INC Y\n");
if(debug & DEBUG_DECODE) printf("INY\n");
y = y + 1;
flag_change(Z, y == 0x00);
flag_change(N, y & 0x80);
@ -500,6 +516,14 @@ struct CPU6502
break;
}
case 0x70: {
int rel = (read_pc_inc(bus) + 128) % 256 - 128;
if(debug & DEBUG_DECODE) printf("BVS %02X\n", rel);
if(isset(V))
pc += rel;
break;
}
case 0x30: {
int rel = (read_pc_inc(bus) + 128) % 256 - 128;
if(debug & DEBUG_DECODE) printf("BMI %02X\n", rel);
@ -590,6 +614,19 @@ struct CPU6502
break;
}
case 0xF1: {
unsigned char zpg = read_pc_inc(bus);
if(debug & DEBUG_DECODE) printf("SBC (%02X),Y\n", zpg);
int addr = bus.read(zpg) + bus.read(zpg + 1) * 256 + y;
unsigned char m = bus.read(addr);
int borrow = isset(C) ? 0 : 1;
flag_change(C, !(a < m - borrow));
a = a - m - borrow;
flag_change(N, a & 0x80);
flag_change(V, isset(C) != isset(N));
flag_change(Z, a == 0);
break;
}
case 0xED: {
int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256;
if(debug & DEBUG_DECODE) printf("SBC %04X\n", addr);
@ -627,6 +664,18 @@ struct CPU6502
break;
}
case 0x06: {
unsigned char zpg = read_pc_inc(bus);
if(debug & DEBUG_DECODE) printf("ASL %02X\n", zpg);
unsigned char m = bus.read(zpg);
flag_change(C, m & 0x80);
m = m << 1;
flag_change(N, m & 0x80);
flag_change(Z, m == 0);
bus.write(zpg, m);
break;
}
case 0x0A: {
if(debug & DEBUG_DECODE) printf("ASL A\n");
flag_change(C, a & 0x80);
@ -636,6 +685,18 @@ struct CPU6502
break;
}
case 0x46: {
unsigned char zpg = read_pc_inc(bus);
if(debug & DEBUG_DECODE) printf("LSR %02X\n", zpg);
unsigned char m = bus.read(zpg);
flag_change(C, m & 0x01);
m = m >> 1;
flag_change(N, m & 0x80);
flag_change(Z, m == 0);
bus.write(zpg, m);
break;
}
case 0x4E: {
int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256;
if(debug & DEBUG_DECODE) printf("LSR %04X\n", addr);
@ -716,6 +777,16 @@ struct CPU6502
break;
}
case 0x2A: {
if(debug & DEBUG_DECODE) printf("ROL A\n");
bool c = isset(C);
flag_change(C, a & 0x80);
a = (c ? 0x01 : 0x00) | (a << 1);
flag_change(N, a & 0x80);
flag_change(Z, a == 0);
break;
}
case 0x76: {
unsigned char zpg = read_pc_inc(bus) + x;
if(debug & DEBUG_DECODE) printf("ROR %02X\n", zpg);
@ -729,6 +800,19 @@ struct CPU6502
break;
}
case 0x26: {
unsigned char zpg = read_pc_inc(bus) + x;
if(debug & DEBUG_DECODE) printf("ROL %02X\n", zpg);
bool c = isset(C);
unsigned char m = bus.read(zpg);
flag_change(C, m & 0x80);
m = (c ? 0x01 : 0x00) | (m << 1);
flag_change(N, m & 0x80);
flag_change(Z, m == 0);
bus.write(zpg, m);
break;
}
case 0x4C: {
int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256;
if(debug & DEBUG_DECODE) printf("JMP %04X\n", addr);
@ -787,9 +871,19 @@ struct CPU6502
break;
}
case 0x24: {
unsigned char zpg = read_pc_inc(bus);
if(debug & DEBUG_DECODE) printf("BIT %02X\n", zpg);
unsigned char m = bus.read(zpg);
flag_change(Z, a & m);
flag_change(N, m & 0x80);
flag_change(V, m & 0x70);
break;
}
case 0x2C: {
int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256;
if(debug & DEBUG_DECODE) printf("BIT #%04X\n", addr);
if(debug & DEBUG_DECODE) printf("BIT %04X\n", addr);
unsigned char m = bus.read(addr);
flag_change(Z, a & m);
flag_change(N, m & 0x80);
@ -806,6 +900,15 @@ struct CPU6502
break;
}
case 0xA6: {
unsigned char zpg = read_pc_inc(bus);
if(debug & DEBUG_DECODE) printf("LDX %02X\n", zpg);
x = bus.read(zpg);
flag_change(N, x & 0x80);
flag_change(Z, x == 0);
break;
}
case 0xA4: {
unsigned char zpg = read_pc_inc(bus);
if(debug & DEBUG_DECODE) printf("LDY %02X\n", zpg);
@ -863,9 +966,19 @@ struct CPU6502
case 0xCC: {
int addr = read_pc_inc(bus) + read_pc_inc(bus) * 256;
if(debug & DEBUG_DECODE) printf("CPY %04X\n", addr);
unsigned char imm = bus.read(addr);
flag_change(C, imm <= a);
imm = a - imm;
unsigned char m = bus.read(addr);
flag_change(C, m <= a);
m = a - m;
flag_change(N, m & 0x80);
flag_change(Z, m == 0);
break;
}
case 0xE0: {
unsigned char imm = read_pc_inc(bus);
if(debug & DEBUG_DECODE) printf("CPX %02X\n", imm);
flag_change(C, imm <= x);
imm = x - imm;
flag_change(N, imm & 0x80);
flag_change(Z, imm == 0);
break;
@ -874,8 +987,8 @@ struct CPU6502
case 0xC0: {
unsigned char imm = read_pc_inc(bus);
if(debug & DEBUG_DECODE) printf("CPY %02X\n", imm);
flag_change(C, imm <= a);
imm = a - imm;
flag_change(C, imm <= y);
imm = y - imm;
flag_change(N, imm & 0x80);
flag_change(Z, imm == 0);
break;
@ -965,8 +1078,19 @@ struct CPU6502
break;
}
case 0xE4: {
unsigned char zpg = read_pc_inc(bus);
if(debug & DEBUG_DECODE) printf("CPX %02X\n", zpg);
unsigned char m = bus.read(zpg);
flag_change(C, m <= x);
m = x - m;
flag_change(N, m & 0x80);
flag_change(Z, m == 0);
break;
}
case 0xC4: {
unsigned char zpg = read_pc_inc(bus) + x;
unsigned char zpg = read_pc_inc(bus);
if(debug & DEBUG_DECODE) printf("CPY %02X\n", zpg);
unsigned char m = bus.read(zpg);
flag_change(C, m <= y);
@ -1020,7 +1144,6 @@ struct CPU6502
unsigned char pcl = stack_pull(bus);
unsigned char pch = stack_pull(bus);
pc = pcl + pch * 256 + 1;
printf("%02X %02X, %04X\n", pcl, pch, pc);
break;
}