core: Fixes SBCI

Thanks to <evgeny.chukreev@gmail.com>

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

diff --git a/simavr/sim/sim_core.c b/simavr/sim/sim_core.c
index 1ccae6b..3901ede 100644 (file)
--- a/simavr/sim/sim_core.c
+++ b/simavr/sim/sim_core.c
@@ -707,7 +707,8 @@ uint16_t avr_run_one(avr_t * avr)
                        uint8_t res = vr - k - avr->sreg[S_C];
                        STATE("sbci %s[%02x], 0x%02x = %02x\n", avr_regname(r), avr->data[r], k, res);
                        _avr_set_r(avr, r, res);
-                       avr->sreg[S_Z] = res  == 0;
+                       if (res)
+                               avr->sreg[S_Z] = 0;
                        avr->sreg[S_N] = (res >> 7) & 1;
                        avr->sreg[S_C] = (k + avr->sreg[S_C]) > vr;
                        avr->sreg[S_S] = avr->sreg[S_N] ^ avr->sreg[S_V];