diff options
Diffstat (limited to 'main.myr')
| -rw-r--r-- | main.myr | 47 |
1 files changed, 41 insertions, 6 deletions
@@ -54,16 +54,51 @@ const main = { var mem : uint8[memsz] var reg : uint8[regsz] var stk : uint16[stksz] - var I : uint16 - var pc : uint16 - var sp : uint16 - var delay : uint8 - var sound : uint8 + var pc : uint16 = 0x200 + var sp : uint16 = 0 + var I : uint16 = 0 + var delay : uint8 = 0 + var sound : uint8 = 0 clrscr(&gfx, scrsz) - loadprg(&mem, "/home/jakob/Airplane.ch8") + var opcode, arg + + while true + opcode = mem[pc] + arg = mem[pc + 1] + match (opcode & 0xf0) >> 4 + | 0x0: + // CLS + if (opcode & 0x0f) == 0 && (arg & 0x0f) == 0 + clrscr(&gfx, scrsz) + // RET + elif (opcode & 0x0f) == 0 + if sp == 0 + std.die("stack underflow") + ;; + pc = stk[sp] + sp-- + // SYS + else + std.die("RCA 1802 SYS unimplemted\n") + ;; + // JP + | 0x1: + pc = ((opcode & 0x0f) << 8) | arg + // CALL + | 0x2: + sp++ + if sp > stksz + std.die("stack overflow") + ;; + stk[sp] = pc + pc = ((opcode & 0x0f) << 8) | arg + | _ : std.die("unimplemented opcode\n") + ;; + ;; + sdl.update(tex, (gfx[:] : void#), 64) sdl.copy(r, tex) sdl.present(r) |