WIP: trying to restructure

2 files changed, 151 insertions, 41 deletions

diff --git a/instr.c b/instr.c
new file mode 100644
index 0000000..bef859d
--- /dev/null
+++ b/instr.c
@@ -0,0 +1,149 @@
+typedef enum
+{
+                                    C8_ILL,
+/* Onnn = 0,1,2,A,B              */
+/*    00E0 - CLS                 */ C8_CLS,
+/*    00EE - RET                 */ C8_RET,
+/*    0nnn - SYS  addr           */ C8_SYS,
+/*    1nnn - JP   addr           */ C8_JP,
+/*    2nnn - CALL addr           */ C8_CALL,
+/*    Annn - LD   I,  addr       */ C8_LDI,
+/*    Bnnn - JP   V0, addr       */ C8_JPV,
+/* Oxkk = 3,4,6,7,C,E,F          */
+/*    3xkk - SE   Vx, byte       */ C8_SEB,
+/*    4xkk - SNE  Vx, byte       */ C8_SNEB,
+/*    6xkk - LD   Vx, byte       */ C8_LD,
+/*    7xkk - ADD  Vx, byte       */ C8_ADDB,
+/*    Cxkk - RND  Vx, byte       */ C8_RND,
+/*    Ex9E - SKP  Vx             */ C8_SKP,
+/*    ExA1 - SKNP Vx             */ C8_SKNP,
+/*    Fx07 - LD   Vx, DT         */ C8_MVDT,
+/*    Fx0A - LD   Vx, K          */ C8_LDK,
+/*    Fx15 - LD   DT, Vx         */ C8_LDDT,
+/*    Fx18 - LD   ST, Vx         */ C8_LDST,
+/*    Fx1E - ADD  I, Vx          */ C8_ADDI,
+/*    Fx29 - LD   F, Vx          */ C8_HEX,
+/*    Fx33 - LD   B, Vx          */ C8_BCD,
+/*    Fx55 - LD   [I], Vx        */ C8_SAVE,
+/*    Fx65 - LD   Vx, [I]        */ C8_RESTORE,
+/* Oxyn = 5,8,9,D                */
+/*    5xy0 - SE   Vx, Vy         */ C8_SE,
+/*    8xy0 - LD   Vx, Vy         */ C8_MOVE,
+/*    8xy1 - OR   Vx, Vy         */ C8_OR,
+/*    8xy2 - AND  Vx, Vy         */ C8_AND,
+/*    8xy3 - XOR  Vx, Vy         */ C8_XOR,
+/*    8xy4 - ADD  Vx, Vy         */ C8_ADD,
+/*    8xy5 - SUB  Vx, Vy         */ C8_SUB,
+/*    8xy6 - SHR  Vx {, Vy}      */ C8_SHR,
+/*    8xy7 - SUBN Vx, Vy         */ C8_SUBN,
+/*    8xyE - SHL  Vx {, Vy}      */ C8_SHL,
+/*    9xy0 - SNE  Vx, Vy         */ C8_SNE,
+/*    Dxyn - DRW  Vx, Vy, nibble */ C8_DRW,
+    C8_OP_CNT
+
+} chip8_op;
+
+typedef void (*instr_func)(chip8* c8, chip8_op op, u16 nnn, u8 x, u8 y, u8 n, u8 kk);
+
+
+const char* chip8_disasm_fmts[C8_OP_CNT] =
+{
+    "ILL  unknown",
+    "CLS",
+    "RET",
+    "SYS  %03X",
+    "JP   %03X",
+    "CALL %03X",
+    "LD   I,  %03X",
+    "JP   V0, %03X",
+    "SE   V%-2x, %-2d",
+    "SNE  V%-2x, %-2d",
+    "LD   V%-2x, %-2d",
+    "ADD  V%-2x, %-2d",
+    "RND  V%-2x, %-2d",
+    "SKP  V%-2x",
+    "SKNP V%-2x",
+    "LD   V%-2x, DT",
+    "LD   V%-2x, K",
+    "LD   DT, V%-2x",
+    "LD   ST, V%-2x",
+    "ADD  I, V%-2x",
+    "LD   F, V%-2x",
+    "LD   B, V%-2x",
+    "LD   [I], V%-2x",
+    "LD   V%-2x, [I]",
+    "SE   V%-2x, V%-2x",
+    "LD   V%-2x, V%-2x",
+    "OR   V%-2x, V%-2x",
+    "AND  V%-2x, V%-2x",
+    "XOR  V%-2x, V%-2x",
+    "ADD  V%-2x, V%-2x",
+    "SUB  V%-2x, V%-2x",
+    "SHR  V%-2x, V%-2x",
+    "SUBN V%-2x, V%-2x",
+    "SHL  V%-2x, V%-2x",
+    "SNE  V%-2x, V%-2x",
+    "DRW  V%-2x, V%-2x, %-1d"
+};
+
+void c8_decode(u8* code, u16 offset, instr_func func, chip8* c8);
+void c8_disasm(chip8* c8, chip8_op op, u16 nnn, u8 x, u8 y, u8 n, u8 kk);
+void c8_do(chip8* c8, chip8_op op, u16 nnn, u8 x, u8 y, u8 n, u8 kk);
+
+void c8_decode(u8* code, u16 offset, instr_func func, chip8* c8)
+{
+    chip8_op op = C8_ILL;
+    u16 word, instr, nnn;
+    u8  o, x, y, n, kk;
+
+    word  = *(u16*)(code + offset);
+    instr = be16toh(word);
+    o     = (instr & 0xF000) >> 12;
+    nnn   = (instr & 0x0FFF);
+    x     = (instr & 0x0F00) >> 8;
+    y     = (instr & 0x00F0) >> 4;
+    n     = (instr & 0x000F);
+    kk    = (instr & 0x00FF);
+
+    if(o == 0 && nnn == 0x0E0)      op = C8_CLS;
+    else if(o == 0 && nnn == 0x0EE) op = C8_RET;
+    else if(o == 0)                 op = C8_SYS;
+    else if(o == 1)                 op = C8_JP;
+    else if(o == 2)                 op = C8_CALL;
+    else if(o == 0xA)               op = C8_LDI;
+    else if(o == 0xB)               op = C8_JPV;
+    else if(o == 3)                 op = C8_SEB;
+    else if(o == 4)                 op = C8_SNEB;
+    else if(o == 6)                 op = C8_LD;
+    else if(o == 7)                 op = C8_ADDB;
+    else if(o == 0xC)               op = C8_RND;
+    else if(o == 0xE && kk == 0x9E) op = C8_SKP;
+    else if(o == 0xE && kk == 0xA1) op = C8_SKNP;
+    else if(o == 0xF && kk == 0x07) op = C8_MVDT;
+    else if(o == 0xF && kk == 0x0A) op = C8_LDK;
+    else if(o == 0xF && kk == 0x15) op = C8_LDDT;
+    else if(o == 0xF && kk == 0x18) op = C8_LDST;
+    else if(o == 0xF && kk == 0x1E) op = C8_ADDI;
+    else if(o == 0xF && kk == 0x29) op = C8_HEX;
+    else if(o == 0xF && kk == 0x33) op = C8_BCD;
+    else if(o == 0xF && kk == 0x55) op = C8_SAVE;
+    else if(o == 0xF && kk == 0x65) op = C8_RESTORE;
+    else if(o == 5 && n == 0)       op = C8_SE;
+    else if(o == 8 && n == 0)       op = C8_MOVE;
+    else if(o == 8 && n == 1)       op = C8_OR;
+    else if(o == 8 && n == 2)       op = C8_AND;
+    else if(o == 8 && n == 3)       op = C8_XOR;
+    else if(o == 8 && n == 4)       op = C8_ADD;
+    else if(o == 8 && n == 5)       op = C8_SUB;
+    else if(o == 8 && n == 6)       op = C8_SHR;
+    else if(o == 8 && n == 7)       op = C8_SUBN;
+    else if(o == 8 && n == 0xE)     op = C8_SHL;
+    else if(o == 9 && n == 0)       op = C8_SNE;
+    else if(o == 0xD)               op = C8_DRW;
+
+    func(c8, op, nnn, x, y, n, kk);
+}
+
+void c8_disasm(chip8* c8, chip8_op op, u16 nnn, u8 x, u8 y, u8 kk, u8 n);
+void c8_do(chip8* c8, chip8_op op, u16 nnn, u8 x, u8 y, u8 kk, u8 n);
+
diff --git a/main.c b/main.c
index d6771ce..c082914 100644
--- a/main.c
+++ b/main.c
@@ -46,6 +46,8 @@ typedef struct
 
 } chip8;
 
+#include "instr.c"
+
 #define V       mem.sys.v
 #define STACK   mem.sys.stack
 #define DISPLAY mem.sys.disp
@@ -64,47 +66,6 @@ void c8_reset(chip8* c8)
     c8->pc = C8_RESET_VECTOR;
 }
 
-/* inst. fmts:
- *   Onnn = 0,1,2,A,B
- *      00E0 - CLS
- *      00EE - RET
- *      0nnn - SYS  addr
- *      1nnn - JP   addr
- *      2nnn - CALL addr
- *      Annn - LD   I,  addr
- *      Bnnn - JP   V0, addr
- *   Oxkk = 3,4,6,7,C,E,F
- *      3xkk - SE   Vx, byte
- *      4xkk - SNE  Vx, byte
- *      6xkk - LD   Vx, byte
- *      7xkk - ADD  Vx, byte
- *      Cxkk - RND  Vx, byte
- *      Ex9E - SKP  Vx
- *      ExA1 - SKNP Vx
- *      Fx07 - LD   Vx, DT
- *      Fx0A - LD   Vx, K
- *      Fx15 - LD   DT, Vx
- *      Fx18 - LD   ST, Vx
- *      Fx1E - ADD  I, Vx
- *      Fx29 - LD   F, Vx
- *      Fx33 - LD   B, Vx
- *      Fx55 - LD   [I], Vx
- *      Fx65 - LD   Vx, [I]
- *   Oxyn = 5,8,9,D
- *      5xy0 - SE   Vx, Vy
- *      8xy0 - LD   Vx, Vy
- *      8xy1 - OR   Vx, Vy
- *      8xy2 - AND  Vx, Vy
- *      8xy3 - XOR  Vx, Vy
- *      8xy4 - ADD  Vx, Vy
- *      8xy5 - SUB  Vx, Vy
- *      8xy6 - SHR  Vx {, Vy}
- *      8xy7 - SUBN Vx, Vy
- *      8xyE - SHL  Vx {, Vy}
- *      9xy0 - SNE  Vx, Vy
- *      Dxyn - DRW  Vx, Vy, nibble
- */
-
 void c8_dump_state(chip8* c8, bool stack)
 {
     int i = 0;