From: Paolo Bonzini <pbonzini@redhat.com>
Date: Tue, 20 Sep 2022 15:48:14 +0000 (+0200)
Subject: target/i386: clarify (un)signedness of immediates from 0F3Ah opcodes
X-Git-Tag: v7.2.0~96^2~12
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=a64eee3ab402469b536db9aeb259097b84d31d0f;p=mirror_qemu.git

target/i386: clarify (un)signedness of immediates from 0F3Ah opcodes

Three-byte opcodes from the 0F3Ah area all have an immediate byte which
is usually unsigned.  Clarify in the helper code that it is unsigned;
the new decoder treats immediates as signed by default, and seeing
an intN_t in the prototype might give the wrong impression that one
can use decode->immediate directly.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---

diff --git a/target/i386/ops_sse.h b/target/i386/ops_sse.h
index 090ba013b3..e7830ff277 100644
--- a/target/i386/ops_sse.h
+++ b/target/i386/ops_sse.h
@@ -1605,17 +1605,17 @@ SSE_HELPER_W(helper_psignw, FSIGNW)
 SSE_HELPER_L(helper_psignd, FSIGNL)
 
 void glue(helper_palignr, SUFFIX)(CPUX86State *env, Reg *d, Reg *v, Reg *s,
-                                  int32_t shift)
+                                  uint32_t imm)
 {
     int i;
 
     /* XXX could be checked during translation */
-    if (shift >= (SHIFT ? 32 : 16)) {
+    if (imm >= (SHIFT ? 32 : 16)) {
         for (i = 0; i < (1 << SHIFT); i++) {
             d->Q(i) = 0;
         }
     } else {
-        shift <<= 3;
+        int shift = imm * 8;
 #define SHR(v, i) (i < 64 && i > -64 ? i > 0 ? v >> (i) : (v << -(i)) : 0)
 #if SHIFT == 0
         d->Q(0) = SHR(s->Q(0), shift - 0) |
@@ -2093,7 +2093,7 @@ static inline int pcmp_val(Reg *r, uint8_t ctrl, int i)
 }
 
 static inline unsigned pcmpxstrx(CPUX86State *env, Reg *d, Reg *s,
-                                 int8_t ctrl, int valids, int validd)
+                                 uint8_t ctrl, int valids, int validd)
 {
     unsigned int res = 0;
     int v;
diff --git a/target/i386/ops_sse_header.h b/target/i386/ops_sse_header.h
index 440f1c0e78..98178be148 100644
--- a/target/i386/ops_sse_header.h
+++ b/target/i386/ops_sse_header.h
@@ -335,7 +335,7 @@ DEF_HELPER_4(glue(pshufb, SUFFIX), void, env, Reg, Reg, Reg)
 DEF_HELPER_4(glue(psignb, SUFFIX), void, env, Reg, Reg, Reg)
 DEF_HELPER_4(glue(psignw, SUFFIX), void, env, Reg, Reg, Reg)
 DEF_HELPER_4(glue(psignd, SUFFIX), void, env, Reg, Reg, Reg)
-DEF_HELPER_5(glue(palignr, SUFFIX), void, env, Reg, Reg, Reg, s32)
+DEF_HELPER_5(glue(palignr, SUFFIX), void, env, Reg, Reg, Reg, i32)
 
 /* SSE4.1 op helpers */
 #if SHIFT >= 1