diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h index 1c883fa836..325ebbeb98 100644 --- a/target/ppc/cpu.h +++ b/target/ppc/cpu.h @@ -1052,10 +1052,12 @@ struct CPUPPCState { /* Special purpose registers */ target_ulong spr[1024]; ppc_spr_t spr_cb[1024]; - /* Vector status and control register */ + /* Vector status and control register, minus VSCR_SAT. */ uint32_t vscr; /* VSX registers (including FP and AVR) */ ppc_vsr_t vsr[64] QEMU_ALIGNED(16); + /* Non-zero if and only if VSCR_SAT should be set. */ + ppc_vsr_t vscr_sat QEMU_ALIGNED(16); /* SPE registers */ uint64_t spe_acc; uint32_t spe_fscr; diff --git a/target/ppc/int_helper.c b/target/ppc/int_helper.c index 1d8a4b530b..6ad596a08b 100644 --- a/target/ppc/int_helper.c +++ b/target/ppc/int_helper.c @@ -459,18 +459,23 @@ void helper_lvsr(ppc_avr_t *r, target_ulong sh) void helper_mtvscr(CPUPPCState *env, uint32_t vscr) { - env->vscr = vscr; + env->vscr = vscr & ~(1u << VSCR_SAT); + /* Which bit we set is completely arbitrary, but clear the rest. */ + env->vscr_sat.u64[0] = vscr & (1u << VSCR_SAT); + env->vscr_sat.u64[1] = 0; set_flush_to_zero((vscr >> VSCR_NJ) & 1, &env->vec_status); } uint32_t helper_mfvscr(CPUPPCState *env) { - return env->vscr; + uint32_t sat = (env->vscr_sat.u64[0] | env->vscr_sat.u64[1]) != 0; + return env->vscr | (sat << VSCR_SAT); } static inline void set_vscr_sat(CPUPPCState *env) { - env->vscr |= 1 << VSCR_SAT; + /* The choice of non-zero value is arbitrary. */ + env->vscr_sat.u32[0] = 1; } void helper_vaddcuw(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b)