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authorvin <git@vineetk.net>2024-06-30 19:10:29 -0400
committervin <git@vineetk.net>2024-06-30 19:10:29 -0400
commita4b39966aed8d41ad4ddc6700683c4779e8d1cb2 (patch)
tree8fab3574f3d83199a4965ffecd0db549105ff96c
parentf28733401ebfe5457a4a79a37fbd5d2001de90bd (diff)
start refactoring opcode defs into an array
-rw-r--r--cpu.c18
-rw-r--r--cpu.h62
-rw-r--r--opcodes.h184
3 files changed, 248 insertions, 16 deletions
diff --git a/cpu.c b/cpu.c
index 0bbbc75..edfe172 100644
--- a/cpu.c
+++ b/cpu.c
@@ -4,6 +4,8 @@
#include <stdlib.h>
#include <string.h>
+#include "cpu.h"
+#include "opcodes.h"
#include "rom.h"
#define MAX(a, b) ((a > b) ? a : b)
@@ -52,22 +54,6 @@ struct registers regs = {0};
struct Rom rom = {0};
-enum addressing_mode {
- AM_ACC,
- AM_IMPLICIT,
- AM_IMM,
- AM_ZP,
- AM_ZP_X,
- AM_ZP_Y,
- AM_REL,
- AM_ABS,
- AM_ABS_X,
- AM_ABS_Y,
- AM_IND,
- AM_IND_X,
- AM_IND_Y,
-};
-
/* 64K address space, 16bit words */
uint8_t memory[0x16000];
diff --git a/cpu.h b/cpu.h
new file mode 100644
index 0000000..139ad83
--- /dev/null
+++ b/cpu.h
@@ -0,0 +1,62 @@
+#include <stdint.h>
+
+void ADC(uint16_t arg);
+void AND(uint16_t arg);
+void ASL_acc(uint16_t arg);
+void ASL(uint16_t arg);
+void BCC(uint16_t arg);
+void BCS(uint16_t arg);
+void BEQ(uint16_t arg);
+void BIT(uint16_t arg);
+void BMI(uint16_t arg);
+void BNE(uint16_t arg);
+void BPL(uint16_t arg);
+void BRK(uint16_t arg);
+void BVC(uint16_t arg);
+void BVS(uint16_t arg);
+void CLC(uint16_t arg);
+void CLD(uint16_t arg);
+void CLI(uint16_t arg);
+void CLV(uint16_t arg);
+void CMP(uint16_t arg);
+void CPX(uint16_t arg);
+void CPY(uint16_t arg);
+void DEC(uint16_t arg);
+void DEX(uint16_t arg);
+void DEY(uint16_t arg);
+void EOR(uint16_t arg);
+void INC(uint16_t arg);
+void INX(uint16_t arg);
+void INY(uint16_t arg);
+void JMP(uint16_t arg);
+void JSR(uint16_t arg);
+void LDA(uint16_t arg);
+void LDX(uint16_t arg);
+void LDY(uint16_t arg);
+void LSR_acc(uint16_t arg);
+void LSR(uint16_t arg);
+void NOP(uint16_t arg);
+void ORA(uint16_t arg);
+void PHA(uint16_t arg);
+void PHP(uint16_t arg);
+void PLA(uint16_t arg);
+void PLP(uint16_t arg);
+void ROL_acc(uint16_t arg);
+void ROL(uint16_t arg);
+void ROR_acc(uint16_t arg);
+void ROR(uint16_t arg);
+void RTI(uint16_t arg);
+void RTS(uint16_t arg);
+void SBC(uint16_t arg);
+void SEC(uint16_t arg);
+void SED(uint16_t arg);
+void SEI(uint16_t arg);
+void STA(uint16_t arg);
+void STX(uint16_t arg);
+void STY(uint16_t arg);
+void TAX(uint16_t arg);
+void TAY(uint16_t arg);
+void TSX(uint16_t arg);
+void TXA(uint16_t arg);
+void TXS(uint16_t arg);
+void TYA(uint16_t arg);
diff --git a/opcodes.h b/opcodes.h
new file mode 100644
index 0000000..defc427
--- /dev/null
+++ b/opcodes.h
@@ -0,0 +1,184 @@
+#include <stdint.h>
+
+#include "cpu.h"
+
+enum addressing_mode {
+ AM_NONE,
+ AM_ACC,
+ AM_IMM,
+ AM_REL,
+ AM_ZP,
+ AM_ZP_X,
+ AM_ZP_Y,
+ AM_ABS,
+ AM_ABS_X,
+ AM_ABS_Y,
+ AM_IND,
+ AM_IND_X,
+ AM_IND_Y,
+};
+
+/* index of below array is the code of the instruction */
+struct opcode {
+ const char name[4];
+ /* I know 16bit seems wasteful, but some ops use 16bit memory as arg */
+ void (*instr)(uint16_t arg);
+ uint8_t bytes;
+ uint8_t cycles;
+ enum addressing_mode mode;
+};
+
+struct opcode opcodes[0x100] = {
+ /* official opcodes */
+ [0x69] = { "ADC", ADC, 2, 2, AM_IMM },
+ [0x65] = { "ADC", ADC, 2, 3, AM_ZP },
+ [0x75] = { "ADC", ADC, 2, 4, AM_ZP_X },
+ [0x6D] = { "ADC", ADC, 3, 4, AM_ABS },
+ [0x7D] = { "ADC", ADC, 3, 4, AM_ABS_X },
+ [0x79] = { "ADC", ADC, 3, 4, AM_ABS_Y },
+ [0x61] = { "ADC", ADC, 2, 6, AM_IND_X },
+ [0x71] = { "ADC", ADC, 2, 5, AM_IND_Y },
+ [0x29] = { "AND", AND, 2, 2, AM_IMM },
+ [0x25] = { "AND", AND, 2, 3, AM_ZP },
+ [0x35] = { "AND", AND, 2, 4, AM_ZP_X },
+ [0x2D] = { "AND", AND, 3, 4, AM_ABS },
+ [0x3D] = { "AND", AND, 3, 4, AM_ABS_X },
+ [0x39] = { "AND", AND, 3, 4, AM_ABS_Y },
+ [0x21] = { "AND", AND, 2, 6, AM_IND_X },
+ [0x31] = { "AND", AND, 2, 5, AM_IND_Y },
+ [0x0A] = { "ASL", ASL_acc, 1, 2, AM_ACC },
+ [0x06] = { "ASL", ASL, 2, 5, AM_ZP },
+ [0x16] = { "ASL", ASL, 2, 6, AM_ZP_X },
+ [0x0E] = { "ASL", ASL, 3, 6, AM_ABS },
+ [0x1E] = { "ASL", ASL, 3, 7, AM_ABS_X },
+ [0x90] = { "BCC", BCC, 2, 2, AM_REL },
+ [0xB0] = { "BCS", BCS, 2, 2, AM_REL },
+ [0xF0] = { "BEQ", BEQ, 2, 2, AM_REL },
+ [0x24] = { "BIT", BIT, 2, 3, AM_ZP },
+ [0x2C] = { "BIT", BIT, 3, 4, AM_ABS },
+ [0x30] = { "BMI", BMI, 2, 2, AM_REL },
+ [0xD0] = { "BNE", BNE, 2, 2, AM_REL },
+ [0x10] = { "BPL", BPL, 2, 2, AM_REL },
+ [0x00] = { "BRK", BRK, 1, 7, AM_NONE },
+ [0x50] = { "BVC", BVC, 2, 2, AM_REL },
+ [0x70] = { "BVS", BVS, 2, 2, AM_REL },
+ [0x18] = { "CLC", CLC, 1, 2, AM_NONE },
+ [0xD8] = { "CLD", CLD, 1, 2, AM_NONE },
+ [0x58] = { "CLI", CLI, 1, 2, AM_NONE },
+ [0xB8] = { "CLV", CLV, 1, 2, AM_NONE },
+ [0xC9] = { "CMP", CMP, 2, 2, AM_IMM },
+ [0xC5] = { "CMP", CMP, 2, 3, AM_ZP },
+ [0xD5] = { "CMP", CMP, 2, 4, AM_ZP_X },
+ [0xCD] = { "CMP", CMP, 3, 4, AM_ABS },
+ [0xDD] = { "CMP", CMP, 3, 4, AM_ABS_X },
+ [0xD9] = { "CMP", CMP, 3, 4, AM_ABS_Y },
+ [0xC1] = { "CMP", CMP, 2, 6, AM_IND_X },
+ [0xD1] = { "CMP", CMP, 2, 5, AM_IND_Y },
+ [0xE0] = { "CPX", CPX, 2, 2, AM_IMM },
+ [0xE4] = { "CPX", CPX, 2, 3, AM_ZP },
+ [0xEC] = { "CPX", CPX, 3, 4, AM_ABS },
+ [0xC0] = { "CPY", CPY, 2, 2, AM_IMM },
+ [0xC4] = { "CPY", CPY, 2, 3, AM_ZP },
+ [0xCC] = { "CPY", CPY, 3, 4, AM_ABS },
+ [0xC6] = { "DEC", DEC, 2, 5, AM_ZP },
+ [0xD6] = { "DEC", DEC, 2, 6, AM_ZP_X },
+ [0xCE] = { "DEC", DEC, 3, 6, AM_ABS },
+ [0xDE] = { "DEC", DEC, 3, 7, AM_ABS_X },
+ [0xCA] = { "DEX", DEX, 1, 2, AM_NONE },
+ [0x88] = { "DEY", DEY, 1, 2, AM_NONE },
+ [0x49] = { "EOR", EOR, 2, 2, AM_IMM },
+ [0x45] = { "EOR", EOR, 2, 3, AM_ZP },
+ [0x55] = { "EOR", EOR, 2, 4, AM_ZP_X },
+ [0x4D] = { "EOR", EOR, 3, 4, AM_ABS },
+ [0x5D] = { "EOR", EOR, 3, 4, AM_ABS_X },
+ [0x59] = { "EOR", EOR, 3, 4, AM_ABS_Y },
+ [0x41] = { "EOR", EOR, 2, 6, AM_IND_X },
+ [0x51] = { "EOR", EOR, 2, 5, AM_IND_Y },
+ [0xE6] = { "INC", INC, 2, 5, AM_ZP },
+ [0xF6] = { "INC", INC, 2, 6, AM_ZP_X },
+ [0xEE] = { "INC", INC, 3, 6, AM_ABS },
+ [0xFE] = { "INC", INC, 3, 7, AM_ABS_X },
+ [0xE8] = { "INX", INX, 1, 2, AM_NONE },
+ [0xC8] = { "INY", INY, 1, 2, AM_NONE },
+ [0x4C] = { "JMP", JMP, 3, 3, AM_ABS },
+ [0x6C] = { "JMP", JMP, 3, 5, AM_IND },
+ [0x20] = { "JSR", JSR, 3, 6, AM_ABS },
+ [0xA9] = { "LDA", LDA, 2, 2, AM_IMM },
+ [0xA5] = { "LDA", LDA, 2, 3, AM_ZP },
+ [0xB5] = { "LDA", LDA, 2, 4, AM_ZP_X },
+ [0xAD] = { "LDA", LDA, 3, 4, AM_ABS },
+ [0xBD] = { "LDA", LDA, 3, 4, AM_ABS_X },
+ [0xB9] = { "LDA", LDA, 3, 4, AM_ABS_Y },
+ [0xA1] = { "LDA", LDA, 2, 6, AM_IND_X },
+ [0xB1] = { "LDA", LDA, 2, 5, AM_IND_Y },
+ [0xA2] = { "LDX", LDX, 2, 2, AM_IMM },
+ [0xA6] = { "LDX", LDX, 2, 3, AM_ZP },
+ [0xB6] = { "LDX", LDX, 2, 4, AM_ZP_Y },
+ [0xAE] = { "LDX", LDX, 3, 4, AM_ABS },
+ [0xBE] = { "LDX", LDX, 3, 4, AM_ABS_Y },
+ [0xA0] = { "LDY", LDY, 2, 2, AM_IMM },
+ [0xA4] = { "LDY", LDY, 2, 3, AM_ZP },
+ [0xB4] = { "LDY", LDY, 2, 4, AM_ZP_X },
+ [0xAC] = { "LDY", LDY, 3, 4, AM_ABS },
+ [0xBC] = { "LDY", LDY, 3, 4, AM_ABS_X },
+ [0x4A] = { "LSR", LSR_acc, 1, 2, AM_ACC },
+ [0x46] = { "LSR", LSR, 2, 5, AM_ZP },
+ [0x56] = { "LSR", LSR, 2, 6, AM_ZP_X },
+ [0x4E] = { "LSR", LSR, 3, 6, AM_ABS },
+ [0x5E] = { "LSR", LSR, 3, 7, AM_ABS_X },
+ [0xEA] = { "NOP", NOP, 1, 2, AM_NONE },
+ [0x09] = { "ORA", ORA, 2, 2, AM_IMM },
+ [0x05] = { "ORA", ORA, 2, 3, AM_ZP },
+ [0x15] = { "ORA", ORA, 2, 4, AM_ZP_X },
+ [0x0D] = { "ORA", ORA, 3, 4, AM_ABS },
+ [0x1D] = { "ORA", ORA, 3, 4, AM_ABS_X },
+ [0x19] = { "ORA", ORA, 3, 4, AM_ABS_Y },
+ [0x01] = { "ORA", ORA, 2, 6, AM_IND_X },
+ [0x11] = { "ORA", ORA, 2, 5, AM_IND_Y },
+ [0x48] = { "PHA", PHA, 1, 3, AM_NONE },
+ [0x08] = { "PHP", PHP, 1, 3, AM_NONE },
+ [0x68] = { "PLA", PLA, 1, 4, AM_NONE },
+ [0x28] = { "PLP", PLP, 1, 4, AM_NONE },
+ [0x2A] = { "ROL", ROL_acc, 1, 2, AM_ACC },
+ [0x26] = { "ROL", ROL, 2, 5, AM_ZP },
+ [0x36] = { "ROL", ROL, 2, 6, AM_ZP_X },
+ [0x2E] = { "ROL", ROL, 3, 6, AM_ABS },
+ [0x3E] = { "ROL", ROL, 3, 7, AM_ABS_X },
+ [0x6A] = { "ROR", ROR_acc, 1, 2, AM_ACC },
+ [0x66] = { "ROR", ROR, 2, 5, AM_ZP },
+ [0x76] = { "ROR", ROR, 2, 6, AM_ZP_X },
+ [0x6E] = { "ROR", ROR, 3, 6, AM_ABS },
+ [0x7E] = { "ROR", ROR, 3, 7, AM_ABS_X },
+ [0x40] = { "RTI", RTI, 1, 6, AM_NONE },
+ [0x60] = { "RTS", RTS, 1, 6, AM_NONE },
+ [0xE9] = { "SBC", SBC, 2, 2, AM_IMM },
+ [0xE5] = { "SBC", SBC, 2, 3, AM_ZP },
+ [0xF5] = { "SBC", SBC, 2, 4, AM_ZP_X },
+ [0xED] = { "SBC", SBC, 3, 4, AM_ABS },
+ [0xFD] = { "SBC", SBC, 3, 4, AM_ABS_X },
+ [0xF9] = { "SBC", SBC, 3, 4, AM_ABS_Y },
+ [0xE1] = { "SBC", SBC, 2, 6, AM_IND_X },
+ [0xF1] = { "SBC", SBC, 2, 5, AM_IND_Y },
+ [0x38] = { "SEC", SEC, 1, 2, AM_NONE },
+ [0xF8] = { "SED", SED, 1, 2, AM_NONE },
+ [0x78] = { "SEI", SEI, 1, 2, AM_NONE },
+ [0x85] = { "STA", STA, 2, 3, AM_ZP },
+ [0x95] = { "STA", STA, 2, 4, AM_ZP_X },
+ [0x8D] = { "STA", STA, 3, 4, AM_ABS },
+ [0x9D] = { "STA", STA, 3, 5, AM_ABS_X },
+ [0x99] = { "STA", STA, 3, 5, AM_ABS_Y },
+ [0x81] = { "STA", STA, 2, 6, AM_IND_X },
+ [0x91] = { "STA", STA, 2, 6, AM_IND_Y },
+ [0x86] = { "STX", STX, 2, 3, AM_ZP },
+ [0x96] = { "STX", STX, 2, 4, AM_ZP_Y },
+ [0x8E] = { "STX", STX, 3, 4, AM_ABS },
+ [0x84] = { "STY", STY, 2, 3, AM_ZP },
+ [0x94] = { "STY", STY, 2, 4, AM_ZP_X },
+ [0x8C] = { "STY", STY, 3, 4, AM_ABS },
+ [0xAA] = { "TAX", TAX, 1, 2, AM_NONE },
+ [0xA8] = { "TAY", TAY, 1, 2, AM_NONE },
+ [0xBA] = { "TSX", TSX, 1, 2, AM_NONE },
+ [0x8A] = { "TXA", TXA, 1, 2, AM_NONE },
+ [0x9A] = { "TXS", TXS, 1, 2, AM_NONE },
+ [0x98] = { "TYA", TYA, 1, 2, AM_NONE },
+};