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| author | Jakob L. Kreuze <zerodaysfordays@sdf.lonestar.org> | 2020-01-01 14:00:18 -0500 |
|---|---|---|
| committer | Jakob L. Kreuze <zerodaysfordays@sdf.lonestar.org> | 2020-01-01 14:00:18 -0500 |
| commit | 2346e752d01524c40cc1c4671247798c89802de9 (patch) | |
| tree | ad956142cbd3694ae210cf1febd1feb575781e82 | |
| parent | 39027f3fa356e5d00815564116b07f43103ce0d5 (diff) | |
Implement register arithmetic instructions.
| -rw-r--r-- | main.myr | 52 |
1 files changed, 52 insertions, 0 deletions
@@ -117,8 +117,60 @@ const main = { // LD | 0x6: reg[opcode & 0x0f] = arg + // ADD (without overflow) + | 0x7: + reg[opcode & 0x0f] += arg + | 0x8: + match arg & 0x0f + // LD + | 0x0: + reg[opcode & 0x0f] = reg[(arg & 0xf0) >> 8] + // OR + | 0x1: + reg[opcode & 0x0f] |= reg[(arg & 0xf0) >> 8] + // AND + | 0x2: + reg[opcode & 0x0f] &= reg[(arg & 0xf0) >> 8] + // XOR + | 0x3: + reg[opcode & 0x0f] ^= reg[(arg & 0xf0) >> 8] + // ADD + | 0x4: + if (0xff - reg[opcode & 0x0f]) < reg[(arg & 0xf0) >> 8] + reg[0xf] = 1 + else + reg[0xf] = 0 + ;; + reg[opcode & 0x0f] += reg[(arg & 0xf0) >> 8] + // SUB + | 0x5: + if (0xff - reg[opcode & 0x0f]) < reg[(arg & 0xf0) >> 8] + reg[0xf] = 1 + else + reg[0xf] = 0 + ;; + reg[opcode & 0x0f] -= reg[(arg & 0xf0) >> 8] + // SHR + | 0x6: + reg[0xf] = reg[opcode & 0x0f] & 1 + reg[opcode & 0x0f] >>= 1 + // SUBN + | 0x7: + if (0xff - reg[(arg & 0xf0) >> 8]) < reg[opcode & 0x0f] + reg[0xf] = 1 + else + reg[0xf] = 0 + ;; + reg[opcode & 0x0f] = reg[(arg & 0xf0) >> 8] - reg[opcode & 0x0f] + // SHL + | 0xe: + reg[0xf] = reg[opcode & 0x0f] & (1 << 7) + reg[opcode & 0x0f] <<= 1 + | _: std.die("unimplemented opcode\n") + ;; | _ : std.die("unimplemented opcode\n") ;; + pc += 2 ;; sdl.update(tex, (gfx[:] : void#), 64) |