From eb02cc3f89013612cb05df23b5441741e902bbd2 Mon Sep 17 00:00:00 2001 From: Aurelien Jarno Date: Wed, 15 Jul 2015 17:05:09 +0200 Subject: [PATCH] target-mips: simplify LWL/LDL mask generation The LWL/LDL instructions mask the GPR with a mask depending on the address alignement. It is currently computed by doing: mask = 0x7fffffffffffffffull >> (t1 ^ 63) It's simpler to generate it by doing: mask = ~(-1 << t1) It uses one TCG instruction less, and it avoids a 32/64-bit constant loading which can take a few instructions on RISC hosts. Cc: Leon Alrae Signed-off-by: Aurelien Jarno Reviewed-by: Richard Henderson Reviewed-by: Leon Alrae Signed-off-by: Leon Alrae --- target-mips/translate.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/target-mips/translate.c b/target-mips/translate.c index 22ef84df9e..98cf72de74 100644 --- a/target-mips/translate.c +++ b/target-mips/translate.c @@ -2153,11 +2153,10 @@ static void gen_ld(DisasContext *ctx, uint32_t opc, tcg_gen_andi_tl(t0, t0, ~7); tcg_gen_qemu_ld_tl(t0, t0, ctx->mem_idx, MO_TEQ); tcg_gen_shl_tl(t0, t0, t1); - tcg_gen_xori_tl(t1, t1, 63); - t2 = tcg_const_tl(0x7fffffffffffffffull); - tcg_gen_shr_tl(t2, t2, t1); + t2 = tcg_const_tl(-1); + tcg_gen_shl_tl(t2, t2, t1); gen_load_gpr(t1, rt); - tcg_gen_and_tl(t1, t1, t2); + tcg_gen_andc_tl(t1, t1, t2); tcg_temp_free(t2); tcg_gen_or_tl(t0, t0, t1); tcg_temp_free(t1); @@ -2246,11 +2245,10 @@ static void gen_ld(DisasContext *ctx, uint32_t opc, tcg_gen_andi_tl(t0, t0, ~3); tcg_gen_qemu_ld_tl(t0, t0, ctx->mem_idx, MO_TEUL); tcg_gen_shl_tl(t0, t0, t1); - tcg_gen_xori_tl(t1, t1, 31); - t2 = tcg_const_tl(0x7fffffffull); - tcg_gen_shr_tl(t2, t2, t1); + t2 = tcg_const_tl(-1); + tcg_gen_shl_tl(t2, t2, t1); gen_load_gpr(t1, rt); - tcg_gen_and_tl(t1, t1, t2); + tcg_gen_andc_tl(t1, t1, t2); tcg_temp_free(t2); tcg_gen_or_tl(t0, t0, t1); tcg_temp_free(t1);