diff options
| author | Aurelien Jarno <aurelien@aurel32.net> | 2015-07-15 17:05:09 +0200 |
|---|---|---|
| committer | Leon Alrae <leon.alrae@imgtec.com> | 2015-08-13 16:22:52 +0100 |
| commit | eb02cc3f89013612cb05df23b5441741e902bbd2 (patch) | |
| tree | 3c520356c13e7cc307cb77db087d1bc795fb8b5a /target-mips | |
| parent | aff2bc6dc6d839caf6df0900437cc2cc9e180605 (diff) | |
| download | qemu-eb02cc3f89013612cb05df23b5441741e902bbd2.zip | |
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 <leon.alrae@imgtec.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Leon Alrae <leon.alrae@imgtec.com>
Signed-off-by: Leon Alrae <leon.alrae@imgtec.com>
Diffstat (limited to 'target-mips')
| -rw-r--r-- | target-mips/translate.c | 14 |
1 files 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); |