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From: Paolo Bonzini <pbonzini@redhat.com>
To: qemu-devel@nongnu.org
Cc: richard.henderson@linaro.org
Subject: [PATCH 2/4] target/i386: use TSTEQ/TSTNE to check flags
Date: Wed, 28 Feb 2024 12:11:49 +0100	[thread overview]
Message-ID: <20240228111151.287738-3-pbonzini@redhat.com> (raw)
In-Reply-To: <20240228111151.287738-1-pbonzini@redhat.com>

The new condition obviously come in handy when testing individual bits
of EFLAGS, and they make it possible to remove the .mask field of
CCPrepare.

Lowering to shift+and is done by the optimizer if necessary.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/tcg/translate.c | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
index fe9021833e3..63d520e0cba 100644
--- a/target/i386/tcg/translate.c
+++ b/target/i386/tcg/translate.c
@@ -995,8 +995,8 @@ static CCPrepare gen_prepare_eflags_c(DisasContext *s, TCGv reg)
     case CC_OP_EFLAGS:
     case CC_OP_SARB ... CC_OP_SARQ:
         /* CC_SRC & 1 */
-        return (CCPrepare) { .cond = TCG_COND_NE,
-                             .reg = cpu_cc_src, .mask = CC_C };
+        return (CCPrepare) { .cond = TCG_COND_TSTNE,
+                             .reg = cpu_cc_src, .mask = -1, .imm = CC_C };
 
     default:
        /* The need to compute only C from CC_OP_DYNAMIC is important
@@ -1013,8 +1013,8 @@ static CCPrepare gen_prepare_eflags_c(DisasContext *s, TCGv reg)
 static CCPrepare gen_prepare_eflags_p(DisasContext *s, TCGv reg)
 {
     gen_compute_eflags(s);
-    return (CCPrepare) { .cond = TCG_COND_NE, .reg = cpu_cc_src,
-                         .mask = CC_P };
+    return (CCPrepare) { .cond = TCG_COND_TSTNE, .reg = cpu_cc_src,
+                         .mask = -1, .imm = CC_P };
 }
 
 /* compute eflags.S to reg */
@@ -1028,8 +1028,8 @@ static CCPrepare gen_prepare_eflags_s(DisasContext *s, TCGv reg)
     case CC_OP_ADCX:
     case CC_OP_ADOX:
     case CC_OP_ADCOX:
-        return (CCPrepare) { .cond = TCG_COND_NE, .reg = cpu_cc_src,
-                             .mask = CC_S };
+        return (CCPrepare) { .cond = TCG_COND_TSTNE, .reg = cpu_cc_src,
+                             .mask = -1, .imm = CC_S };
     case CC_OP_CLR:
     case CC_OP_POPCNT:
         return (CCPrepare) { .cond = TCG_COND_NEVER, .mask = -1 };
@@ -1057,8 +1057,8 @@ static CCPrepare gen_prepare_eflags_o(DisasContext *s, TCGv reg)
                              .reg = cpu_cc_src, .mask = -1 };
     default:
         gen_compute_eflags(s);
-        return (CCPrepare) { .cond = TCG_COND_NE, .reg = cpu_cc_src,
-                             .mask = CC_O };
+        return (CCPrepare) { .cond = TCG_COND_TSTNE, .reg = cpu_cc_src,
+                             .mask = -1, .imm = CC_O };
     }
 }
 
@@ -1073,8 +1073,8 @@ static CCPrepare gen_prepare_eflags_z(DisasContext *s, TCGv reg)
     case CC_OP_ADCX:
     case CC_OP_ADOX:
     case CC_OP_ADCOX:
-        return (CCPrepare) { .cond = TCG_COND_NE, .reg = cpu_cc_src,
-                             .mask = CC_Z };
+        return (CCPrepare) { .cond = TCG_COND_TSTNE, .reg = cpu_cc_src,
+                             .mask = -1, .imm = CC_Z };
     case CC_OP_CLR:
         return (CCPrepare) { .cond = TCG_COND_ALWAYS, .mask = -1 };
     case CC_OP_POPCNT:
@@ -1152,8 +1152,8 @@ static CCPrepare gen_prepare_cc(DisasContext *s, int b, TCGv reg)
             break;
         case JCC_BE:
             gen_compute_eflags(s);
-            cc = (CCPrepare) { .cond = TCG_COND_NE, .reg = cpu_cc_src,
-                               .mask = CC_Z | CC_C };
+            cc = (CCPrepare) { .cond = TCG_COND_TSTNE, .reg = cpu_cc_src,
+                               .mask = -1, .imm = CC_Z | CC_C };
             break;
         case JCC_S:
             cc = gen_prepare_eflags_s(s, reg);
@@ -1167,8 +1167,8 @@ static CCPrepare gen_prepare_cc(DisasContext *s, int b, TCGv reg)
                 reg = s->tmp0;
             }
             tcg_gen_addi_tl(reg, cpu_cc_src, CC_O - CC_S);
-            cc = (CCPrepare) { .cond = TCG_COND_NE, .reg = reg,
-                               .mask = CC_O };
+            cc = (CCPrepare) { .cond = TCG_COND_TSTNE, .reg = reg,
+                               .mask = -1, .imm = CC_O };
             break;
         default:
         case JCC_LE:
@@ -1177,8 +1177,8 @@ static CCPrepare gen_prepare_cc(DisasContext *s, int b, TCGv reg)
                 reg = s->tmp0;
             }
             tcg_gen_addi_tl(reg, cpu_cc_src, CC_O - CC_S);
-            cc = (CCPrepare) { .cond = TCG_COND_NE, .reg = reg,
-                               .mask = CC_O | CC_Z };
+            cc = (CCPrepare) { .cond = TCG_COND_TSTNE, .reg = reg,
+                               .mask = -1, .imm = CC_O | CC_Z };
             break;
         }
         break;
-- 
2.43.2



  parent reply	other threads:[~2024-02-28 11:13 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-28 11:11 [PATCH 0/4] target/i386: use TSTEQ/TSTNE in x86 frontend Paolo Bonzini
2024-02-28 11:11 ` [PATCH 1/4] target/i386: use TSTEQ/TSTNE to test low bits Paolo Bonzini
2024-02-28 22:28   ` Richard Henderson
2024-02-28 11:11 ` Paolo Bonzini [this message]
2024-02-28 22:34   ` [PATCH 2/4] target/i386: use TSTEQ/TSTNE to check flags Richard Henderson
2024-02-28 11:11 ` [PATCH 3/4] target/i386: remove mask from CCPrepare Paolo Bonzini
2024-02-28 22:36   ` Richard Henderson
2024-02-28 11:11 ` [PATCH 4/4] tcg/optimize: optimize TSTNE using smask and zmask Paolo Bonzini
2024-02-28 23:10   ` Richard Henderson
2024-02-29  9:35     ` Paolo Bonzini
2024-02-29 17:17       ` Richard Henderson

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