From ffe30937c89dd67a53bf3f35b962701cd9d8f70e Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Tue, 19 Feb 2013 23:52:15 -0800 Subject: [PATCH] target-ppc: Compute addition overflow without branches Cc: Alexander Graf Signed-off-by: Richard Henderson Signed-off-by: Blue Swirl --- target-ppc/translate.c | 46 ++++++++++++------------------------------ 1 file changed, 13 insertions(+), 33 deletions(-) diff --git a/target-ppc/translate.c b/target-ppc/translate.c index 7aab6ae31cb2..116cf12b3e1b 100644 --- a/target-ppc/translate.c +++ b/target-ppc/translate.c @@ -746,35 +746,23 @@ static void gen_isel(DisasContext *ctx) static inline void gen_op_arith_compute_ov(DisasContext *ctx, TCGv arg0, TCGv arg1, TCGv arg2, int sub) { - int l1; - TCGv t0; + TCGv t0 = tcg_temp_new(); - l1 = gen_new_label(); - /* Start with XER OV disabled, the most likely case */ - tcg_gen_movi_tl(cpu_ov, 0); - t0 = tcg_temp_local_new(); - tcg_gen_xor_tl(t0, arg0, arg1); -#if defined(TARGET_PPC64) - if (!ctx->sf_mode) - tcg_gen_ext32s_tl(t0, t0); -#endif - if (sub) - tcg_gen_brcondi_tl(TCG_COND_LT, t0, 0, l1); - else - tcg_gen_brcondi_tl(TCG_COND_GE, t0, 0, l1); + tcg_gen_xor_tl(cpu_ov, arg0, arg1); tcg_gen_xor_tl(t0, arg1, arg2); + if (sub) { + tcg_gen_and_tl(cpu_ov, cpu_ov, t0); + } else { + tcg_gen_andc_tl(cpu_ov, cpu_ov, t0); + } + tcg_temp_free(t0); #if defined(TARGET_PPC64) - if (!ctx->sf_mode) - tcg_gen_ext32s_tl(t0, t0); + if (!ctx->sf_mode) { + tcg_gen_ext32s_tl(cpu_ov, cpu_ov); + } #endif - if (sub) - tcg_gen_brcondi_tl(TCG_COND_GE, t0, 0, l1); - else - tcg_gen_brcondi_tl(TCG_COND_LT, t0, 0, l1); - tcg_gen_movi_tl(cpu_ov, 1); - tcg_gen_movi_tl(cpu_so, 1); - gen_set_label(l1); - tcg_temp_free(t0); + tcg_gen_shri_tl(cpu_ov, cpu_ov, TARGET_LONG_BITS - 1); + tcg_gen_or_tl(cpu_so, cpu_so, cpu_ov); } static inline void gen_op_arith_compute_ca(DisasContext *ctx, TCGv arg1, @@ -837,10 +825,6 @@ static inline void gen_op_arith_add(DisasContext *ctx, TCGv ret, TCGv arg1, /* Start with XER CA disabled, the most likely case */ tcg_gen_movi_tl(cpu_ca, 0); } - if (compute_ov) { - /* Start with XER OV disabled, the most likely case */ - tcg_gen_movi_tl(cpu_ov, 0); - } tcg_gen_add_tl(t0, arg1, arg2); @@ -1261,10 +1245,6 @@ static inline void gen_op_arith_subf(DisasContext *ctx, TCGv ret, TCGv arg1, /* Start with XER CA disabled, the most likely case */ tcg_gen_movi_tl(cpu_ca, 0); } - if (compute_ov) { - /* Start with XER OV disabled, the most likely case */ - tcg_gen_movi_tl(cpu_ov, 0); - } if (add_ca) { tcg_gen_not_tl(t0, arg1);