[PATCH 01/29] target/ppc: Migrate extswsli to decodetree

[Chinmay Rath <rathc@linux.ibm.com>]

From: Nikhil Kumar Singh <nikhilks@linux.ibm.com>

Move EXTSWSLI to decodetree using the XS-form layout with a custom
%xs_sh field to represent the fractured shift encoding.

This replaces legacy GEN_HANDLER-based implementations with a single
trans_EXTSWSLI() handler.

The implementation intentionally operates directly on the destination
GPR to preserve exact TCG output and avoid introducing temporary
variables, matching legacy behavior.

Testing:
  - Verified TCG equivalence with legacy implementation.

Signed-off-by: Nikhil Kumar Singh <nikhilks@linux.ibm.com>
Signed-off-by: Chinmay Rath <rathc@linux.ibm.com>
---
 target/ppc/insn32.decode |  8 ++++++++
 target/ppc/translate.c   | 43 ++++++++++++++--------------------------
 2 files changed, 23 insertions(+), 28 deletions(-)

diff --git a/target/ppc/insn32.decode b/target/ppc/insn32.decode
index 0e9c68f2fb..342e65dadf 100644
--- a/target/ppc/insn32.decode
+++ b/target/ppc/insn32.decode
@@ -117,6 +117,11 @@
 &X_sa_rc        rs ra rc
 @X_sa_rc        ...... rs:5 ra:5 ..... .......... rc:1          &X_sa_rc
 
+# XS-form with fractured shift amount
+%xs_sh           1:1 11:5
+&XS              rs ra sh rc
+@XS              ...... rs:5 ra:5 ..... ......... . rc:1        &XS sh=%xs_sh
+
 %x_frtp         22:4 !function=times_2
 %x_frap         17:4 !function=times_2
 %x_frbp         12:4 !function=times_2
@@ -1301,6 +1306,9 @@ XVF64GERPN      111011 ... -- .... 0 ..... 10111010 ..-  @XX3_at xa=%xx_xa_pair
 XVF64GERNP      111011 ... -- .... 0 ..... 01111010 ..-  @XX3_at xa=%xx_xa_pair
 XVF64GERNN      111011 ... -- .... 0 ..... 11111010 ..-  @XX3_at xa=%xx_xa_pair
 
+##Extend Sign Word and Shift Left Immediate XS-form
+EXTSWSLI         011111 ..... ..... ..... 110111101 . .         @XS
+
 ## Vector Division Instructions
 
 VDIVSW          000100 ..... ..... ..... 00110001011    @VX
diff --git a/target/ppc/translate.c b/target/ppc/translate.c
index 06ed2adf10..e627f48f9e 100644
--- a/target/ppc/translate.c
+++ b/target/ppc/translate.c
@@ -2470,30 +2470,6 @@ static void gen_sradi1(DisasContext *ctx)
     gen_sradi(ctx, 1);
 }
 
-/* extswsli & extswsli. */
-static inline void gen_extswsli(DisasContext *ctx, int n)
-{
-    int sh = SH(ctx->opcode) + (n << 5);
-    TCGv dst = cpu_gpr[rA(ctx->opcode)];
-    TCGv src = cpu_gpr[rS(ctx->opcode)];
-
-    tcg_gen_ext32s_tl(dst, src);
-    tcg_gen_shli_tl(dst, dst, sh);
-    if (unlikely(Rc(ctx->opcode) != 0)) {
-        gen_set_Rc0(ctx, dst);
-    }
-}
-
-static void gen_extswsli0(DisasContext *ctx)
-{
-    gen_extswsli(ctx, 0);
-}
-
-static void gen_extswsli1(DisasContext *ctx)
-{
-    gen_extswsli(ctx, 1);
-}
-
 /* srd & srd. */
 static void gen_srd(DisasContext *ctx)
 {
@@ -5750,6 +5726,21 @@ static bool resolve_PLS_D(DisasContext *ctx, arg_D *d, arg_PLS_D *a)
     return true;
 }
 
+static bool trans_EXTSWSLI(DisasContext *ctx, arg_XS *a)
+{
+    REQUIRE_64BIT(ctx);
+    REQUIRE_INSNS_FLAGS2(ctx, ISA300);
+
+    /* Mimic legacy behavior: operate directly on dst */
+    tcg_gen_ext32s_tl(cpu_gpr[a->ra], cpu_gpr[a->rs]);
+    tcg_gen_shli_tl(cpu_gpr[a->ra], cpu_gpr[a->ra], a->sh);
+
+    if (unlikely(a->rc)) {
+        gen_set_Rc0(ctx, cpu_gpr[a->ra]);
+    }
+    return true;
+}
+
 #include "translate/fixedpoint-impl.c.inc"
 
 #include "translate/fp-impl.c.inc"
@@ -5850,10 +5841,6 @@ GEN_HANDLER(srad, 0x1F, 0x1A, 0x18, 0x00000000, PPC_64B),
 GEN_HANDLER2(sradi0, "sradi", 0x1F, 0x1A, 0x19, 0x00000000, PPC_64B),
 GEN_HANDLER2(sradi1, "sradi", 0x1F, 0x1B, 0x19, 0x00000000, PPC_64B),
 GEN_HANDLER(srd, 0x1F, 0x1B, 0x10, 0x00000000, PPC_64B),
-GEN_HANDLER2_E(extswsli0, "extswsli", 0x1F, 0x1A, 0x1B, 0x00000000,
-               PPC_NONE, PPC2_ISA300),
-GEN_HANDLER2_E(extswsli1, "extswsli", 0x1F, 0x1B, 0x1B, 0x00000000,
-               PPC_NONE, PPC2_ISA300),
 #endif
 /* handles lfdp, lxsd, lxssp */
 GEN_HANDLER_E(dform39, 0x39, 0xFF, 0xFF, 0x00000000, PPC_NONE, PPC2_ISA205),
-- 
2.55.0