sam/6502
1
0
Fork 0
mirror of https://github.com/raxracks/6502.git synced 2024-07-07 21:31:17 +12:00
Code Issues Packages Projects Releases Wiki Activity

add cpu flags

Browse source
This commit is contained in:
raxracks 2024-01-28 10:04:41 +13:00
parent 86384b76a3
commit e3bf688026
6 changed files with 155 additions and 59 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

BIN
emulator
View file

Binary file not shown.

170
emulator.c
View file

@ -3,13 +3,13 @@
#include <stdint.h> #include <stdint.h>
#include <assert.h> #include <assert.h>
#define NEGATIVE 1 << 7 uint8_t N = 1 << 7;
#define OVERFLOW 1 << 6 uint8_t V = 1 << 6;
#define BREAK 1 << 4 uint8_t B = 1 << 4;
#define DECIMAL 1 << 3 uint8_t D = 1 << 3;
#define INTERRUPT 1 << 2 uint8_t I = 1 << 2;
#define ZERO 1 << 1 uint8_t Z = 1 << 1;
#define CARRY 1 << 0 uint8_t C = 1 << 0;
typedef struct { typedef struct {
uint8_t A; uint8_t A;
@ -21,7 +21,23 @@ typedef struct {
} CPU; } CPU;
CPU cpu = { 0 }; CPU cpu = { 0 };
uint8_t* memory; uint8_t* memory;
void add_flag(uint8_t flag) {
cpu.P |= flag;
}
void clear_flag(uint8_t flag) {
cpu.P &= ~flag;
}
void set_flag(uint8_t flag, int condition) {
if(condition == 1) {
add_flag(flag);
} else if(condition == 0) {
clear_flag(flag);
}
}
int main(int argc, char** argv) { int main(int argc, char** argv) {
assert(argc > 1); assert(argc > 1);
@ -44,13 +60,6 @@ int main(int argc, char** argv) {
printf("%d: 0x%02X (h_nib: 0x%X, l_nib: 0x%X)\n", cpu.PC, opcode, h_nib, l_nib); printf("%d: 0x%02X (h_nib: 0x%X, l_nib: 0x%X)\n", cpu.PC, opcode, h_nib, l_nib);
switch(h_nib) { switch(h_nib) {
case 0x0:
switch(l_nib) {
case 0x0:
printf("%c", cpu.A);
break;
}
break;
case 0x8: case 0x8:
switch(l_nib) { switch(l_nib) {
case 0x1: case 0x1:
@ -76,6 +85,10 @@ int main(int argc, char** argv) {
case 0xA: case 0xA:
printf(" ∟ TXA\n"); printf(" ∟ TXA\n");
cpu.A = cpu.X; cpu.A = cpu.X;
set_flag(N, cpu.A & 0x80 != 0);
set_flag(Z, cpu.A == 0);
break; break;
case 0xC: case 0xC:
printf(" ∟ STY $%04X\n", word); printf(" ∟ STY $%04X\n", word);
@ -120,6 +133,10 @@ int main(int argc, char** argv) {
case 0x8: case 0x8:
printf(" ∟ TYA\n"); printf(" ∟ TYA\n");
cpu.A = cpu.Y; cpu.A = cpu.Y;
set_flag(N, cpu.A & 0x80 != 0);
set_flag(Z, cpu.A == 0);
break; break;
case 0x9: case 0x9:
printf(" ∟ STA $%04X, Y\n", word); printf(" ∟ STA $%04X, Y\n", word);
@ -142,61 +159,108 @@ int main(int argc, char** argv) {
case 0x0: case 0x0:
printf(" ∟ LDY #$%02X\n", one); printf(" ∟ LDY #$%02X\n", one);
cpu.Y = one; cpu.Y = one;
set_flag(N, cpu.Y & 0x80 != 0);
set_flag(Z, cpu.Y == 0);
cpu.PC++; cpu.PC++;
break; break;
case 0x1: case 0x1:
printf(" ∟ LDA ($%02X, X)\n", one); printf(" ∟ LDA ($%02X, X)\n", one);
cpu.A = memory[memory[one + cpu.X]]; cpu.A = memory[memory[one + cpu.X]];
printf("addr: %x val: %x\n", memory[one + cpu.X], cpu.A);
set_flag(N, cpu.A & 0x80 != 0);
set_flag(Z, cpu.A == 0);
cpu.PC++; cpu.PC++;
break; break;
case 0x2: case 0x2:
printf(" ∟ LDX #$%02X\n", one); printf(" ∟ LDX #$%02X\n", one);
cpu.X = one; cpu.X = one;
set_flag(N, cpu.X & 0x80 != 0);
set_flag(Z, cpu.X == 0);
cpu.PC++; cpu.PC++;
break; break;
case 0x4: case 0x4:
printf(" ∟ LDY $%02X\n", one); printf(" ∟ LDY $%02X\n", one);
cpu.Y = memory[one]; cpu.Y = memory[one];
set_flag(N, cpu.Y & 0x80 != 0);
set_flag(Z, cpu.Y == 0);
cpu.PC++; cpu.PC++;
break; break;
case 0x5: case 0x5:
printf(" ∟ LDA $%02X\n", one); printf(" ∟ LDA $%02X\n", one);
cpu.A = memory[one]; cpu.A = memory[one];
set_flag(N, cpu.A & 0x80 != 0);
set_flag(Z, cpu.A == 0);
cpu.PC++; cpu.PC++;
break; break;
case 0x6: case 0x6:
printf(" ∟ LDX $%02X\n", one); printf(" ∟ LDX $%02X\n", one);
cpu.X = memory[one]; cpu.X = memory[one];
set_flag(N, cpu.X & 0x80 != 0);
set_flag(Z, cpu.X == 0);
cpu.PC++; cpu.PC++;
break; break;
case 0x8: case 0x8:
printf(" ∟ TAY\n"); printf(" ∟ TAY\n");
cpu.Y = cpu.A; cpu.Y = cpu.A;
set_flag(N, cpu.Y & 0x80 != 0);
set_flag(Z, cpu.Y == 0);
break; break;
case 0x9: case 0x9:
printf(" ∟ LDA #$%02X\n", one); printf(" ∟ LDA #$%02X\n", one);
cpu.A = one; cpu.A = one;
set_flag(N, cpu.A & 0x80 != 0);
set_flag(Z, cpu.A == 0);
cpu.PC++; cpu.PC++;
break; break;
case 0xA: case 0xA:
printf(" ∟ TAX\n"); printf(" ∟ TAX\n");
cpu.X = cpu.A; cpu.X = cpu.A;
set_flag(N, cpu.X & 0x80 != 0);
set_flag(Z, cpu.X == 0);
break; break;
case 0xC: case 0xC:
printf(" ∟ LDY $%04X\n", word); printf(" ∟ LDY $%04X\n", word);
cpu.Y = memory[word]; cpu.Y = memory[word];
set_flag(N, cpu.Y & 0x80 != 0);
set_flag(Z, cpu.Y == 0);
cpu.PC += 2; cpu.PC += 2;
break; break;
case 0xD: case 0xD:
printf(" ∟ LDA $%04X\n", word); printf(" ∟ LDA $%04X\n", word);
cpu.A = memory[word]; cpu.A = memory[word];
set_flag(N, cpu.A & 0x80 != 0);
set_flag(Z, cpu.A == 0);
cpu.PC += 2; cpu.PC += 2;
break; break;
case 0xE: case 0xE:
printf(" ∟ LDX $%04X\n", word); printf(" ∟ LDX $%04X\n", word);
cpu.X = memory[word]; cpu.X = memory[word];
set_flag(N, cpu.X & 0x80 != 0);
set_flag(Z, cpu.X == 0);
cpu.PC += 2; cpu.PC += 2;
break; break;
} }
@ -206,53 +270,81 @@ int main(int argc, char** argv) {
case 0x1: case 0x1:
printf(" ∟ LDA ($%02X), Y\n", one); printf(" ∟ LDA ($%02X), Y\n", one);
cpu.A = memory[memory[one] + cpu.Y]; cpu.A = memory[memory[one] + cpu.Y];
printf("addr: %x val: %x\n", memory[one] + cpu.Y, cpu.A);
set_flag(N, cpu.A & 0x80 != 0);
set_flag(Z, cpu.A == 0);
cpu.PC++; cpu.PC++;
break; break;
case 0x4: case 0x4:
printf(" ∟ LDY $%02X, X\n", one); printf(" ∟ LDY $%02X, X\n", one);
cpu.Y = memory[one + cpu.X]; cpu.Y = memory[one + cpu.X];
printf("addr: %x val: %x\n", one + cpu.X, cpu.Y);
set_flag(N, cpu.Y & 0x80 != 0);
set_flag(Z, cpu.Y == 0);
cpu.PC++; cpu.PC++;
break; break;
case 0x5: case 0x5:
printf(" ∟ LDA $%02X, X\n", one); printf(" ∟ LDA $%02X, X\n", one);
cpu.A = memory[one + cpu.X]; cpu.A = memory[one + cpu.X];
printf("addr: %x val: %x\n", one + cpu.X, cpu.A);
set_flag(N, cpu.A & 0x80 != 0);
set_flag(Z, cpu.A == 0);
cpu.PC++; cpu.PC++;
break; break;
case 0x6: case 0x6:
printf(" ∟ LDX $%02X, Y\n", one); printf(" ∟ LDX $%02X, Y\n", one);
cpu.X = memory[one + cpu.Y]; cpu.X = memory[one + cpu.Y];
printf("addr: %x val: %x\n", one + cpu.Y, cpu.X);
set_flag(N, cpu.X & 0x80 != 0);
set_flag(Z, cpu.X == 0);
cpu.PC++; cpu.PC++;
break; break;
case 0x9: case 0x9:
printf(" ∟ LDA $%04X, Y\n", word); printf(" ∟ LDA $%04X, Y\n", word);
cpu.A = memory[word + cpu.Y]; cpu.A = memory[word + cpu.Y];
printf("addr: %x val: %x\n", word + cpu.Y, cpu.A);
set_flag(N, cpu.A & 0x80 != 0);
set_flag(Z, cpu.A == 0);
cpu.PC++; cpu.PC++;
break; break;
case 0xA: case 0xA:
printf("TSX\n"); printf("TSX\n");
cpu.X = cpu.SP; cpu.X = cpu.SP;
set_flag(N, cpu.X & 0x80 != 0);
set_flag(Z, cpu.X == 0);
break; break;
case 0xC: case 0xC:
printf(" ∟ LDY $%04X, X\n", word); printf(" ∟ LDY $%04X, X\n", word);
cpu.Y = memory[word + cpu.X]; cpu.Y = memory[word + cpu.X];
printf("addr: %x val: %x\n", word + cpu.X, cpu.Y);
set_flag(N, cpu.Y & 0x80 != 0);
set_flag(Z, cpu.Y == 0);
cpu.PC += 2; cpu.PC += 2;
break; break;
case 0xD: case 0xD:
printf(" ∟ LDA $%04X, X\n", word); printf(" ∟ LDA $%04X, X\n", word);
cpu.A = memory[word + cpu.X]; cpu.A = memory[word + cpu.X];
printf("addr: %x val: %x\n", word + cpu.X, cpu.A);
set_flag(N, cpu.A & 0x80 != 0);
set_flag(Z, cpu.A == 0);
cpu.PC += 2; cpu.PC += 2;
break; break;
case 0xE: case 0xE:
printf(" ∟ LDX $%04X, Y\n", word); printf(" ∟ LDX $%04X, Y\n", word);
cpu.X = memory[word + cpu.Y]; cpu.X = memory[word + cpu.Y];
printf("addr: %x val: %x\n", word + cpu.Y, cpu.X);
set_flag(N, cpu.X & 0x80 != 0);
set_flag(Z, cpu.X == 0);
cpu.PC += 2; cpu.PC += 2;
break; break;
} }
@ -262,6 +354,10 @@ int main(int argc, char** argv) {
case 0x8: case 0x8:
printf(" ∟ INY\n"); printf(" ∟ INY\n");
cpu.Y++; cpu.Y++;
set_flag(N, cpu.Y & 0x80 != 0);
set_flag(Z, cpu.Y == 0);
break; break;
} }
break; break;
@ -270,11 +366,19 @@ int main(int argc, char** argv) {
case 0x6: case 0x6:
printf(" ∟ INC $%02X\n", one); printf(" ∟ INC $%02X\n", one);
memory[one]++; memory[one]++;
set_flag(N, memory[one] & 0x80 != 0);
set_flag(Z, memory[one] == 0);
cpu.PC++; cpu.PC++;
break; break;
case 0x8: case 0x8:
printf(" ∟ INX\n"); printf(" ∟ INX\n");
cpu.X++; cpu.X++;
set_flag(N, cpu.X & 0x80 != 0);
set_flag(Z, cpu.X == 0);
break; break;
case 0xA: case 0xA:
printf(" ∟ NOP\n"); printf(" ∟ NOP\n");
@ -282,6 +386,10 @@ int main(int argc, char** argv) {
case 0xE: case 0xE:
printf(" ∟ INC $%04X\n", word); printf(" ∟ INC $%04X\n", word);
memory[word]++; memory[word]++;
set_flag(N, memory[word] & 0x80 != 0);
set_flag(Z, memory[word] == 0);
cpu.PC += 2; cpu.PC += 2;
break; break;
} }
@ -290,12 +398,22 @@ int main(int argc, char** argv) {
switch(l_nib) { switch(l_nib) {
case 0x6: case 0x6:
printf(" ∟ INC $%02X, X\n", one); printf(" ∟ INC $%02X, X\n", one);
memory[one + cpu.X]++; uint8_t addr = one + cpu.X;
memory[addr]++;
set_flag(N, memory[addr] & 0x80 != 0);
set_flag(Z, memory[addr] == 0);
cpu.PC++; cpu.PC++;
break; break;
case 0xE: case 0xE:
printf(" ∟ INC $%04X, X\n", word); printf(" ∟ INC $%04X, X\n", word);
memory[word + cpu.X]++; uint16_t addr = word + cpu.X;
memory[addr]++;
set_flag(N, memory[addr] & 0x80 != 0);
set_flag(Z, cpu.Y == 0);
cpu.PC += 2; cpu.PC += 2;
break; break;
} }

BIN
hello
View file

Binary file not shown.

32
hello.asm
View file

@ -1,27 +1,5 @@
LDX #0 LDY #$10
LDA hello, X LDY #$f9
BRK LDY #$10
INX LDY #$0
LDA hello, X LDY #$ff
BRK
INX
LDA hello, X
BRK
INX
LDA hello, X
BRK
INX
LDA hello, X
BRK
INX
LDA hello, X
BRK
INX
LDA hello, X
BRK
INX
LDA hello, X
BRK
.DATA
hello: .byte "hello\n", 0

BIN
hello.o
View file

Binary file not shown.

12
implemented.txt
View file

@ -1,23 +1,23 @@
==== LDA (completed) ==== ==== LDA (completed) ====
LDA # LDA #
LDA $ (Z) - LDA $ (Z)
LDA $ (A) LDA $ (A)
LDA $, X (Z) LDA $, X (Z)
LDA $, X (A) LDA $, X (A)
LDA $, Y (A) LDA $, Y (A)
LDA ($, X) - LDA ($, X)
LDA ($), Y LDA ($), Y
==== LDX (completed) ==== ==== LDX (completed) ====
LDX # - LDX #
LDX $ (Z) - LDX $ (Z)
LDX $ (A) LDX $ (A)
LDX $, Y (Z) LDX $, Y (Z)
LDX $, Y (A) LDX $, Y (A)
==== LDY (completed) ==== ==== LDY (completed) ====
LDY # - LDY #
LDY $ (Z) - LDY $ (Z)
LDY $ (A) LDY $ (A)
LDY $, X (Z) LDY $, X (Z)
LDY $, X (A) LDY $, X (A)