On 6/2/19 4:08 AM, Mark Cave-Ayland wrote:
> void helper_xvxsigsp(CPUPPCState *env, uint32_t opcode)
> {
> - ppc_vsr_t xt, xb;
> + ppc_vsr_t *xt = &env->vsr[xT(opcode)];
> + ppc_vsr_t *xb = &env->vsr[xB(opcode)];
> + ppc_vsr_t t = *xt;
> uint32_t exp, i, fraction;
>
> - getVSR(xB(opcode), &xb, env);
> - memset(&xt, 0, sizeof(xt));
Change in behaviour -- zero init to copy init.
Note for future cleanup: most of these initializations do not need to happen,
because we overwrite all elements of T without consuming the previous value.
> @@ -3410,23 +3382,22 @@ void helper_xsrqpi(CPUPPCState *env, uint32_t opcode)
> env->fp_status.float_exception_flags &= ~float_flag_inexact;
> }
>
> - helper_compute_fprf_float128(env, xt.f128);
> + helper_compute_fprf_float128(env, t.f128);
> + *xt = t;
> do_float_check_status(env, GETPC());
> - putVSR(rD(opcode) + 32, &xt, env);
Change in behaviour -- writeback happens before do_float_check_status instead
of after. This may well be a bug fix, but if so should happen separately.
r~
