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authorAurelien Jarno <aurelien@aurel32.net>2015-07-15 17:05:09 +0200
committerLeon Alrae <leon.alrae@imgtec.com>2015-08-13 16:22:52 +0100
commiteb02cc3f89013612cb05df23b5441741e902bbd2 (patch)
tree3c520356c13e7cc307cb77db087d1bc795fb8b5a /target-mips/translate.c
parentaff2bc6dc6d839caf6df0900437cc2cc9e180605 (diff)
downloadqemu-arm-eb02cc3f89013612cb05df23b5441741e902bbd2.tar.gz
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/translate.c')
-rw-r--r--target-mips/translate.c14
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);