core: Fix MULS register

MULS uses 16+ registers.

Signed-off-by: Michel Pollet <buserror@gmail.com>

diff --git a/simavr/sim/sim_core.c b/simavr/sim/sim_core.c
index 3901ede..3550771 100644 (file)
--- a/simavr/sim/sim_core.c
+++ b/simavr/sim/sim_core.c
@@ -517,8 +517,8 @@ uint16_t avr_run_one(avr_t * avr)
                                                                        _avr_set_r(avr, d+1, avr->data[r+1]);
                                                                }       break;
                                                                case 0x0200: {  // MULS – Multiply Signed 0000 0010 dddd rrrr
-                                                                       int8_t r = opcode & 0xf;
-                                                                       int8_t d = (opcode >> 4) & 0xf;
+                                                                       int8_t r = 16 + (opcode & 0xf);
+                                                                       int8_t d = 16 + ((opcode >> 4) & 0xf);
                                                                        int16_t res = ((int8_t)avr->data[r]) * ((int8_t)avr->data[d]);
                                                                        STATE("muls %s[%d], %s[%02x] = %d\n", avr_regname(d), ((int8_t)avr->data[d]), avr_regname(r), ((int8_t)avr->data[r]), res);
                                                                        _avr_set_r(avr, 0, res);