clean up chip-8 into its own file

1 files changed, 105 insertions, 3 deletions

diff --git a/sources/instr.c b/sources/chip8.c
index 72511f1..f5a28a8 100644
--- a/sources/instr.c
+++ b/sources/chip8.c
@@ -1,3 +1,64 @@
+#define C8_RESET_VECTOR     0x200
+#define C8_CYCLES_PER_FRAME 1000
+
+static const u8 fnt[] =
+{
+    0xF0, 0x90, 0x90, 0x90, 0xF0, /* 0 */
+    0x20, 0x60, 0x20, 0x20, 0x70, /* 1 */
+    0xF0, 0x10, 0xF0, 0x80, 0xF0, /* 2 */
+    0xF0, 0x10, 0xF0, 0x10, 0xF0, /* 3 */
+    0x90, 0x90, 0xF0, 0x10, 0x10, /* 4 */
+    0xF0, 0x80, 0xF0, 0x10, 0xF0, /* 5 */
+    0xF0, 0x80, 0xF0, 0x90, 0xF0, /* 6 */
+    0xF0, 0x10, 0x20, 0x40, 0x40, /* 7 */
+    0xF0, 0x90, 0xF0, 0x90, 0xF0, /* 8 */
+    0xF0, 0x90, 0xF0, 0x10, 0xF0, /* 9 */
+    0xF0, 0x90, 0xF0, 0x90, 0x90, /* A */
+    0xE0, 0x90, 0xE0, 0x90, 0xE0, /* B */
+    0xF0, 0x80, 0x80, 0x80, 0xF0, /* C */
+    0xE0, 0x90, 0x90, 0x90, 0xE0, /* D */
+    0xF0, 0x80, 0xF0, 0x80, 0xF0, /* E */
+    0xF0, 0x80, 0xF0, 0x80, 0x80  /* F */
+};
+
+
+typedef struct
+{
+    u16 pc;
+    u8  sp;
+
+    u16 i;
+    u16 keys;
+
+    u64 cycles;
+
+            /* timers: */
+    u8  dt; /* - delay */
+    u8  st; /* - sound */
+
+    bool running;
+
+    union
+    {
+        struct
+        {
+            u8  v[16];
+            u64 disp[32];
+            u8  font[sizeof(fnt)];
+            u16 stack[16];
+
+        } sys;
+        u8 ram[4*KB];
+    } mem;
+
+} chip8;
+
+#define V       mem.sys.v
+#define STACK   mem.sys.stack
+#define DISPLAY mem.sys.disp
+#define FONT    mem.sys.font
+#define RAM     mem.ram
+
 typedef enum
 {
                                     C8_ILL,
@@ -44,6 +105,46 @@ typedef enum
 } chip8_op;
 
 
+void c8_reset(chip8* c8)
+{
+    assert(c8);
+    assert(sizeof(c8->mem) > sizeof(fnt));
+    assert(sizeof(c8->mem) >= 4*KB);
+
+    memcpy(c8->FONT, fnt, sizeof(fnt));
+
+    c8->pc = C8_RESET_VECTOR;
+    c8->running = true;
+}
+
+void c8_dump_state(chip8* c8, bool stack)
+{
+    int i = 0;
+
+    for(i = 0; i < (int)sizeof(c8->V); i += 4)
+    {
+        printf("      V%x: %02X (%3d) ",  i+0, c8->V[i+0], c8->V[i+0]);
+        printf("V%x: %02X (%3d) ",  i+1, c8->V[i+1], c8->V[i+1]);
+        printf("V%x: %02X (%3d) ",  i+2, c8->V[i+2], c8->V[i+2]);
+        printf("V%x: %02X (%3d)\n", i+3, c8->V[i+3], c8->V[i+3]);
+    }
+
+    printf("      I:%04X SP: %02X DT: %02X ST: %02X CYCLES: %llu\n",
+            c8->i, c8->sp, c8->dt, c8->st, c8->cycles);
+
+    if(stack)
+    {
+        printf("stack:\n");
+        for(i = 0; i < (int)sizeof(c8->STACK); i += 2)
+        {
+            printf("      %-2d: %04X ",  i+0, c8->STACK[i+0]);
+            printf("%-2d: %04X\n", i+1, c8->STACK[i+1]);
+        }
+    }
+}
+
+
+
 #define c8_decode_generate(name)                    \
 void c8_##name(u8* code, u16 offset, void* usrdat)  \
 {                                                   \
@@ -68,6 +169,8 @@ void c8_##name(u8* code, u16 offset, void* usrdat)  \
     (void)n;                                        \
     (void)kk;                                       \
                                                     \
+    X_C8_PRELUDE;                                   \
+                                                    \
     if(o == 0 && nnn == 0x0E0)      X_C8_CLS;       \
     else if(o == 0 && nnn == 0x0EE) X_C8_RET;       \
     else if(o == 0)                 X_C8_SYS;       \
@@ -104,7 +207,6 @@ void c8_##name(u8* code, u16 offset, void* usrdat)  \
     else if(o == 9 && n == 0)       X_C8_SNE;       \
     else if(o == 0xD)               X_C8_DRW;       \
     else                            X_C8_ILL;       \
+                                                    \
+    X_C8_EPILOGUE;                                  \
 }
-
-#include "meta/disasm.c"
-#include "meta/exec.c"