diff options
| -rw-r--r-- | src/ahoy/emulator.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/src/ahoy/emulator.c b/src/ahoy/emulator.c index cffc4a9..f774b54 100644 --- a/src/ahoy/emulator.c +++ b/src/ahoy/emulator.c @@ -66,6 +66,8 @@ emuinit(struct u8view prog, const char *fn) void emutick(void) { + if ((size_t)c8.PC + 1 >= lengthof(mem)) + diex("%s: attempted to read instruction beyond end of RAM", filename); opexec((mem[c8.PC] << 8) | mem[c8.PC + 1]); c8.PC += 2; } @@ -209,8 +211,10 @@ opexec(uint16_t op) unsigned y = (op & 0x00F0) >> 4; unsigned n = (op & 0x000F) >> 0; + if (c8.I + n > lengthof(mem)) + diex("%s: attempted to draw sprite beyond bounds of RAM", filename); + for (unsigned i = 0; i < n; i++) { - /* TODO: bounds check? */ uint8_t spr_row = mem[c8.I + i]; uint8_t scr_row = c8.V[y] + i; uint64_t msk; |