[PULL 21/25] target/i386: convert SHLD/SHRD to new decoder

[Paolo Bonzini <pbonzini@redhat.com>]

Use the same flag generation code as SHL and SHR, but use
the existing gen_shiftd_rm_T1 function to compute the result
as well as CC_SRC.

Decoding-wise, SHLD/SHRD by immediate count as a 4 operand
instruction because s->T0 and s->T1 actually occupy three op
slots.  The infrastructure used by opcodes in the 0F 3A table
works fine.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/tcg/translate.c      | 84 +-------------------------------
 target/i386/tcg/decode-new.c.inc |  8 ++-
 target/i386/tcg/emit.c.inc       | 42 ++++++++++++++++
 3 files changed, 50 insertions(+), 84 deletions(-)

diff --git a/target/i386/tcg/translate.c b/target/i386/tcg/translate.c
index 5200b578a0e..33058db4e30 100644
--- a/target/i386/tcg/translate.c
+++ b/target/i386/tcg/translate.c
@@ -1434,57 +1434,11 @@ static bool check_cpl0(DisasContext *s)
     return false;
 }
 
-static void gen_shift_flags(DisasContext *s, MemOp ot, TCGv result,
-                            TCGv shm1, TCGv count, bool is_right)
-{
-    TCGv_i32 z32, s32, oldop;
-    TCGv z_tl;
-
-    /* Store the results into the CC variables.  If we know that the
-       variable must be dead, store unconditionally.  Otherwise we'll
-       need to not disrupt the current contents.  */
-    z_tl = tcg_constant_tl(0);
-    if (cc_op_live[s->cc_op] & USES_CC_DST) {
-        tcg_gen_movcond_tl(TCG_COND_NE, cpu_cc_dst, count, z_tl,
-                           result, cpu_cc_dst);
-    } else {
-        tcg_gen_mov_tl(cpu_cc_dst, result);
-    }
-    if (cc_op_live[s->cc_op] & USES_CC_SRC) {
-        tcg_gen_movcond_tl(TCG_COND_NE, cpu_cc_src, count, z_tl,
-                           shm1, cpu_cc_src);
-    } else {
-        tcg_gen_mov_tl(cpu_cc_src, shm1);
-    }
-
-    /* Get the two potential CC_OP values into temporaries.  */
-    tcg_gen_movi_i32(s->tmp2_i32, (is_right ? CC_OP_SARB : CC_OP_SHLB) + ot);
-    if (s->cc_op == CC_OP_DYNAMIC) {
-        oldop = cpu_cc_op;
-    } else {
-        tcg_gen_movi_i32(s->tmp3_i32, s->cc_op);
-        oldop = s->tmp3_i32;
-    }
-
-    /* Conditionally store the CC_OP value.  */
-    z32 = tcg_constant_i32(0);
-    s32 = tcg_temp_new_i32();
-    tcg_gen_trunc_tl_i32(s32, count);
-    tcg_gen_movcond_i32(TCG_COND_NE, cpu_cc_op, s32, z32, s->tmp2_i32, oldop);
-
-    /* The CC_OP value is no longer predictable.  */
-    set_cc_op(s, CC_OP_DYNAMIC);
-}
-
 /* XXX: add faster immediate case */
-static TCGv gen_shiftd_rm_T1(DisasContext *s, MemOp ot,
-                             bool is_right, TCGv count_in)
+static void gen_shiftd_rm_T1(DisasContext *s, MemOp ot,
+                             bool is_right, TCGv count)
 {
     target_ulong mask = (ot == MO_64 ? 63 : 31);
-    TCGv count;
-
-    count = tcg_temp_new();
-    tcg_gen_andi_tl(count, count_in, mask);
 
     switch (ot) {
     case MO_16:
@@ -1546,8 +1500,6 @@ static TCGv gen_shiftd_rm_T1(DisasContext *s, MemOp ot,
         tcg_gen_or_tl(s->T0, s->T0, s->T1);
         break;
     }
-
-    return count;
 }
 
 #define X86_MAX_INSN_LENGTH 15
@@ -3057,7 +3009,6 @@ static void disas_insn_old(DisasContext *s, CPUState *cpu, int b)
     CPUX86State *env = cpu_env(cpu);
     int prefixes = s->prefix;
     MemOp dflag = s->dflag;
-    TCGv shift;
     MemOp ot;
     int modrm, reg, rm, mod, op, val;
 
@@ -3221,37 +3172,6 @@ static void disas_insn_old(DisasContext *s, CPUState *cpu, int b)
         }
         break;
 
-        /**************************/
-        /* shifts */
-    case 0x1a4: /* shld imm */
-        op = 0;
-        shift = NULL;
-        goto do_shiftd;
-    case 0x1a5: /* shld cl */
-        op = 0;
-        shift = cpu_regs[R_ECX];
-        goto do_shiftd;
-    case 0x1ac: /* shrd imm */
-        op = 1;
-        shift = NULL;
-        goto do_shiftd;
-    case 0x1ad: /* shrd cl */
-        op = 1;
-        shift = cpu_regs[R_ECX];
-    do_shiftd:
-        ot = dflag;
-        modrm = x86_ldub_code(env, s);
-        reg = ((modrm >> 3) & 7) | REX_R(s);
-        gen_ld_modrm(env, s, modrm, ot);
-        if (!shift) {
-            shift = tcg_constant_tl(x86_ldub_code(env, s));
-        }
-        gen_op_mov_v_reg(s, ot, s->T1, reg);
-        shift = gen_shiftd_rm_T1(s, ot, op, shift);
-        gen_st_modrm(env, s, modrm, ot);
-        gen_shift_flags(s, ot, s->T0, s->tmp0, shift, op);
-        break;
-
         /************************/
         /* bit operations */
     case 0x1ba: /* bt/bts/btr/btc Gv, im */
diff --git a/target/i386/tcg/decode-new.c.inc b/target/i386/tcg/decode-new.c.inc
index 1db9d1e2bc3..2d27b07f296 100644
--- a/target/i386/tcg/decode-new.c.inc
+++ b/target/i386/tcg/decode-new.c.inc
@@ -1114,6 +1114,8 @@ static const X86OpEntry opcodes_0F[256] = {
     [0xa0] = X86_OP_ENTRYr(PUSH, FS, w),
     [0xa1] = X86_OP_ENTRYw(POP, FS, w),
     [0xa2] = X86_OP_ENTRY0(CPUID),
+    [0xa4] = X86_OP_ENTRY4(SHLD,  E,v, 2op,v, G,v),
+    [0xa5] = X86_OP_ENTRY3(SHLD,  E,v, 2op,v, G,v),
 
     [0xb2] = X86_OP_ENTRY3(LSS,    G,v, EM,p, None, None),
     [0xb4] = X86_OP_ENTRY3(LFS,    G,v, EM,p, None, None),
@@ -1240,6 +1242,8 @@ static const X86OpEntry opcodes_0F[256] = {
     [0xa8] = X86_OP_ENTRYr(PUSH,   GS, w),
     [0xa9] = X86_OP_ENTRYw(POP,    GS, w),
     [0xaa] = X86_OP_ENTRY0(RSM,             chk(smm) svm(RSM)),
+    [0xac] = X86_OP_ENTRY4(SHRD,   E,v, 2op,v, G,v),
+    [0xad] = X86_OP_ENTRY3(SHRD,   E,v, 2op,v, G,v),
     [0xae] = X86_OP_GROUP0(group15),
     /*
      * It's slightly more efficient to put Ev operand in T0 and allow gen_IMUL3
@@ -2532,8 +2536,8 @@ static void disas_insn(DisasContext *s, CPUState *cpu)
             switch (b) {
             case 0x00 ... 0x01: /* mostly privileged instructions */
             case 0x1a ... 0x1b: /* MPX */
-            case 0xa3 ... 0xa5: /* BT, SHLD */
-            case 0xab ... 0xad: /* BTS, SHRD */
+            case 0xa3:          /* bt */
+            case 0xab:          /* bts */
             case 0xb0 ... 0xb1: /* cmpxchg */
             case 0xb3:          /* btr */
             case 0xb8:          /* integer ops */
diff --git a/target/i386/tcg/emit.c.inc b/target/i386/tcg/emit.c.inc
index 156ea282af4..fc4687a35bd 100644
--- a/target/i386/tcg/emit.c.inc
+++ b/target/i386/tcg/emit.c.inc
@@ -3584,6 +3584,27 @@ static void gen_SHL(DisasContext *s, X86DecodedInsn *decode)
     }
 }
 
+static void gen_SHLD(DisasContext *s, X86DecodedInsn *decode)
+{
+    bool can_be_zero;
+    TCGv count;
+    int unit = decode->e.op3 == X86_TYPE_I ? X86_OP_IMM : X86_OP_INT;
+    MemOp ot = gen_shift_count(s, decode, &can_be_zero, &count, unit);
+
+    if (!count) {
+        return;
+    }
+
+    decode->cc_dst = s->T0;
+    decode->cc_src = s->tmp0;
+    gen_shiftd_rm_T1(s, ot, false, count);
+    if (can_be_zero) {
+        gen_shift_dynamic_flags(s, decode, count, CC_OP_SHLB + ot);
+    } else {
+        decode->cc_op = CC_OP_SHLB + ot;
+    }
+}
+
 static void gen_SHLX(DisasContext *s, X86DecodedInsn *decode)
 {
     MemOp ot = decode->op[0].ot;
@@ -3616,6 +3637,27 @@ static void gen_SHR(DisasContext *s, X86DecodedInsn *decode)
     }
 }
 
+static void gen_SHRD(DisasContext *s, X86DecodedInsn *decode)
+{
+    bool can_be_zero;
+    TCGv count;
+    int unit = decode->e.op3 == X86_TYPE_I ? X86_OP_IMM : X86_OP_INT;
+    MemOp ot = gen_shift_count(s, decode, &can_be_zero, &count, unit);
+
+    if (!count) {
+        return;
+    }
+
+    decode->cc_dst = s->T0;
+    decode->cc_src = s->tmp0;
+    gen_shiftd_rm_T1(s, ot, true, count);
+    if (can_be_zero) {
+        gen_shift_dynamic_flags(s, decode, count, CC_OP_SARB + ot);
+    } else {
+        decode->cc_op = CC_OP_SARB + ot;
+    }
+}
+
 static void gen_SHRX(DisasContext *s, X86DecodedInsn *decode)
 {
     MemOp ot = decode->op[0].ot;
-- 
2.45.1