ppc: Add CNTTZW/CNTTZD instructions

Change-Id: I99448ed94e8ef0cb2ea9fdf6e629757bda595d54
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3054472Reviewed-by: Milad Fa <mfarazma@redhat.com>
Commit-Queue: Junliang Yan <junyan@redhat.com>
Cr-Commit-Position: refs/heads/master@{#75930}

src/codegen/ppc/constants-ppc.h

@@ -1172,6 +1172,10 @@ using Instr = uint32_t;
   V(cntlzw, CNTLZWX, 0x7C000034)       \
   /* Count Leading Zeros Doubleword */ \
   V(cntlzd, CNTLZDX, 0x7C000074)       \
+  /* Count Tailing Zeros Word */       \
+  V(cnttzw, CNTTZWX, 0x7C000434)       \
+  /* Count Tailing Zeros Doubleword */ \
+  V(cnttzd, CNTTZDX, 0x7C000474)       \
   /* Population Count Byte-wise */     \
   V(popcntb, POPCNTB, 0x7C0000F4)      \
   /* Population Count Words */         \

src/diagnostics/ppc/disasm-ppc.cc

@@ -891,12 +891,18 @@ void Decoder::DecodeExt2(Instruction* instr) {
       Format(instr, "cntlzw'. 'ra, 'rs");
       return;
     }
-#if V8_TARGET_ARCH_PPC64
     case CNTLZDX: {
       Format(instr, "cntlzd'. 'ra, 'rs");
       return;
     }
-#endif
+    case CNTTZWX: {
+      Format(instr, "cnttzw'. 'ra, 'rs");
+      return;
+    }
+    case CNTTZDX: {
+      Format(instr, "cnttzd'. 'ra, 'rs");
+      return;
+    }
     case ANDX: {
       Format(instr, "and'.    'ra, 'rs, 'rb");
       return;

src/execution/ppc/simulator-ppc.cc

@@ -2523,7 +2523,6 @@ void Simulator::ExecuteGeneric(Instruction* instr) {
       }
       break;
     }
-#if V8_TARGET_ARCH_PPC64
     case CNTLZDX: {
       int rs = instr->RSValue();
       int ra = instr->RAValue();
@@ -2549,7 +2548,42 @@ void Simulator::ExecuteGeneric(Instruction* instr) {
       }
       break;
     }
-#endif
+    case CNTTZWX: {
+      int rs = instr->RSValue();
+      int ra = instr->RAValue();
+      uint32_t rs_val = static_cast<uint32_t>(get_register(rs));
+      uintptr_t count = __builtin_ctz(rs_val);
+      set_register(ra, count);
+      if (instr->Bit(0)) {  // RC Bit set
+        int bf = 0;
+        if (count > 0) {
+          bf |= 0x40000000;
+        }
+        if (count == 0) {
+          bf |= 0x20000000;
+        }
+        condition_reg_ = (condition_reg_ & ~0xF0000000) | bf;
+      }
+      break;
+    }
+    case CNTTZDX: {
+      int rs = instr->RSValue();
+      int ra = instr->RAValue();
+      uint64_t rs_val = get_register(rs);
+      uintptr_t count = __builtin_ctz(rs_val);
+      set_register(ra, count);
+      if (instr->Bit(0)) {  // RC Bit set
+        int bf = 0;
+        if (count > 0) {
+          bf |= 0x40000000;
+        }
+        if (count == 0) {
+          bf |= 0x20000000;
+        }
+        condition_reg_ = (condition_reg_ & ~0xF0000000) | bf;
+      }
+      break;
+    }
     case ANDX: {
       int rs = instr->RSValue();
       int ra = instr->RAValue();