completed game

include/addressing.h

@@ -1,18 +1,17 @@
 #ifndef ADDRESSING_H
 #define ADDRESSING_H
 
+#include <stdbool.h>
 #include <stdint.h>
-#include <stddef.h>
 
-typedef struct
-{
-    uint8_t (*read8)(uint16_t addr, void *userdata);
-    void (*read16)(uint16_t addr, void *userdata);
+typedef enum {
+    AM_IMP, AM_ACC, AM_IMM, AM_ZP, AM_ZPX, AM_ZPY, AM_ABS, AM_ABSX,
+    AM_ABSY, AM_IND, AM_INDX, AM_INDY, AM_REL
+} addr_mode_t;
 
-    void *userdata;
+typedef struct {
+    uint16_t address;
+    bool page_crossed;
+} addr_result_t;
 
-    // cpu registers
-
-} addr_ctx_t;
-
-#endif
+#endif

include/bus.h

@@ -0,0 +1,24 @@
+#ifndef BUS_H
+#define BUS_H
+
+#include <stdbool.h>
+#include <stdint.h>
+#include "memory.h"
+
+typedef struct Bus6502 {
+    Memory memory;
+    uint8_t keyboard;
+    uint32_t rng_state;
+    bool easy6502_io;
+    bool framebuffer_dirty;
+} Bus6502;
+
+void bus_init(Bus6502 *bus);
+uint8_t bus_read(Bus6502 *bus, uint16_t addr);
+void bus_write(Bus6502 *bus, uint16_t addr, uint8_t value);
+uint16_t bus_read16(Bus6502 *bus, uint16_t addr);
+void bus_write16(Bus6502 *bus, uint16_t addr, uint16_t value);
+void bus_set_keyboard(Bus6502 *bus, uint8_t key);
+void bus_seed_rng(Bus6502 *bus, uint32_t seed);
+
+#endif

include/cpu.h

@@ -1,29 +1,37 @@
 #ifndef CPU_H
 #define CPU_H
 
+#include <stdbool.h>
 #include <stdint.h>
 
-typedef struct
-{
-    uint8_t A;  // accumulator
-    uint8_t X;  // index X
-    uint8_t Y;  // index y
-    uint8_t SP; // stack pointer
-    uint8_t PC; // program counter
-    uint8_t P;  // status flags
+typedef struct Bus6502 Bus6502;
+
+typedef struct CPU6502 {
+    uint8_t A, X, Y;
+    uint8_t SP;
+    uint16_t PC;
+    uint8_t P;
+    bool nmi_pending;
+    bool irq_asserted;
 } CPU6502;
 
-// status flag masks
-#define FLAG_C 0x01
-#define FLAG_Z 0x02
-#define FLAG_I 0x04
-#define FLAG_D 0x08
-#define FLAG_B 0x10
-#define FLAG_U 0x20
-#define FLAG_V 0x40
-#define FLAG_N 0x80
+enum {
+    FLAG_C = 0x01, FLAG_Z = 0x02, FLAG_I = 0x04, FLAG_D = 0x08,
+    FLAG_B = 0x10, FLAG_U = 0x20, FLAG_V = 0x40, FLAG_N = 0x80
+};
 
-void cpu_reset(CPU6502 *cpu);
-void cpu_print_state(CPU6502 *cpu);
+typedef enum { CPU_STEP_OK = 0, CPU_STEP_ILLEGAL_OPCODE } cpu_step_status_t;
 
-#endif
+typedef struct {
+    cpu_step_status_t status;
+    uint8_t opcode;
+    uint8_t cycles;
+} cpu_step_result_t;
+
+void cpu_reset(CPU6502 *cpu, Bus6502 *bus);
+cpu_step_result_t cpu_step(CPU6502 *cpu, Bus6502 *bus);
+void cpu_request_nmi(CPU6502 *cpu);
+void cpu_set_irq(CPU6502 *cpu, bool asserted);
+void cpu_print_state(const CPU6502 *cpu);
+
+#endif

include/frontend.h

@@ -0,0 +1,6 @@
+#ifndef FRONTEND_H
+#define FRONTEND_H
+#include "bus.h"
+#include "cpu.h"
+int frontend_run(CPU6502 *cpu, Bus6502 *bus, unsigned hz, unsigned scale);
+#endif

include/loader.h

@@ -0,0 +1,11 @@
+#ifndef LOADER_H
+#define LOADER_H
+
+#include <stddef.h>
+#include <stdint.h>
+#include "bus.h"
+
+int load_binary(Bus6502 *bus, const char *path, uint16_t address,
+                size_t *bytes_loaded);
+
+#endif

include/opcode.h

@@ -0,0 +1,11 @@
+#ifndef OPCODE_H
+#define OPCODE_H
+
+#include <stddef.h>
+#include <stdint.h>
+#include "bus.h"
+#include "cpu.h"
+
+size_t cpu_disassemble(Bus6502 *bus, uint16_t pc, char *output, size_t size);
+
+#endif