Correct ppc popcntb logic, implement popcntw and popcntd

qemu already includes support for the popcntb instruction introduced
in POWER5 (although it doesn't actually allow you to choose POWER5).

However, the logic is slightly incorrect: it will generate results
truncated to 32-bits when the CPU is in 32-bit mode.  This is not
normal for powerpc - generally arithmetic instructions on a 64-bit
powerpc cpu will generate full 64 bit results, it's just that only the
low 32 bits will be significant for condition codes.

This patch corrects this nit, which actually simplifies the code slightly.

In addition, this patch implements the popcntw and popcntd
instructions added in POWER7, in preparation for allowing POWER7 as an
emulated CPU.

Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

4 files changed, 69 insertions, 11 deletions

diff --git a/target-ppc/cpu.h b/target-ppc/cpu.h
index f293f85976..37dde390a8 100644
--- a/target-ppc/cpu.h
+++ b/target-ppc/cpu.h
@@ -1505,6 +1505,8 @@ enum {
     PPC_DCRX           = 0x2000000000000000ULL,
     /* user-mode DCR access, implemented in PowerPC 460                      */
     PPC_DCRUX          = 0x4000000000000000ULL,
+    /* popcntw and popcntd instructions                                      */
+    PPC_POPCNTWD       = 0x8000000000000000ULL,
 };
 
 /*****************************************************************************/
diff --git a/target-ppc/helper.h b/target-ppc/helper.h
index 2b4744d331..7c02be9cfd 100644
--- a/target-ppc/helper.h
+++ b/target-ppc/helper.h
@@ -38,10 +38,11 @@ DEF_HELPER_2(mulldo, i64, i64, i64)
 
 DEF_HELPER_FLAGS_1(cntlzw, TCG_CALL_CONST | TCG_CALL_PURE, tl, tl)
 DEF_HELPER_FLAGS_1(popcntb, TCG_CALL_CONST | TCG_CALL_PURE, tl, tl)
+DEF_HELPER_FLAGS_1(popcntw, TCG_CALL_CONST | TCG_CALL_PURE, tl, tl)
 DEF_HELPER_2(sraw, tl, tl, tl)
 #if defined(TARGET_PPC64)
 DEF_HELPER_FLAGS_1(cntlzd, TCG_CALL_CONST | TCG_CALL_PURE, tl, tl)
-DEF_HELPER_FLAGS_1(popcntb_64, TCG_CALL_CONST | TCG_CALL_PURE, tl, tl)
+DEF_HELPER_FLAGS_1(popcntd, TCG_CALL_CONST | TCG_CALL_PURE, tl, tl)
 DEF_HELPER_2(srad, tl, tl, tl)
 #endif
 
diff --git a/target-ppc/op_helper.c b/target-ppc/op_helper.c
index aa2e8ba415..b1b883d0a7 100644
--- a/target-ppc/op_helper.c
+++ b/target-ppc/op_helper.c
@@ -499,6 +499,50 @@ target_ulong helper_srad (target_ulong value, target_ulong shift)
 }
 #endif
 
+#if defined(TARGET_PPC64)
+target_ulong helper_popcntb (target_ulong val)
+{
+    val = (val & 0x5555555555555555ULL) + ((val >>  1) &
+                                           0x5555555555555555ULL);
+    val = (val & 0x3333333333333333ULL) + ((val >>  2) &
+                                           0x3333333333333333ULL);
+    val = (val & 0x0f0f0f0f0f0f0f0fULL) + ((val >>  4) &
+                                           0x0f0f0f0f0f0f0f0fULL);
+    return val;
+}
+
+target_ulong helper_popcntw (target_ulong val)
+{
+    val = (val & 0x5555555555555555ULL) + ((val >>  1) &
+                                           0x5555555555555555ULL);
+    val = (val & 0x3333333333333333ULL) + ((val >>  2) &
+                                           0x3333333333333333ULL);
+    val = (val & 0x0f0f0f0f0f0f0f0fULL) + ((val >>  4) &
+                                           0x0f0f0f0f0f0f0f0fULL);
+    val = (val & 0x00ff00ff00ff00ffULL) + ((val >>  8) &
+                                           0x00ff00ff00ff00ffULL);
+    val = (val & 0x0000ffff0000ffffULL) + ((val >> 16) &
+                                           0x0000ffff0000ffffULL);
+    return val;
+}
+
+target_ulong helper_popcntd (target_ulong val)
+{
+    val = (val & 0x5555555555555555ULL) + ((val >>  1) &
+                                           0x5555555555555555ULL);
+    val = (val & 0x3333333333333333ULL) + ((val >>  2) &
+                                           0x3333333333333333ULL);
+    val = (val & 0x0f0f0f0f0f0f0f0fULL) + ((val >>  4) &
+                                           0x0f0f0f0f0f0f0f0fULL);
+    val = (val & 0x00ff00ff00ff00ffULL) + ((val >>  8) &
+                                           0x00ff00ff00ff00ffULL);
+    val = (val & 0x0000ffff0000ffffULL) + ((val >> 16) &
+                                           0x0000ffff0000ffffULL);
+    val = (val & 0x00000000ffffffffULL) + ((val >> 32) &
+                                           0x00000000ffffffffULL);
+    return val;
+}
+#else
 target_ulong helper_popcntb (target_ulong val)
 {
     val = (val & 0x55555555) + ((val >>  1) & 0x55555555);
@@ -507,12 +551,13 @@ target_ulong helper_popcntb (target_ulong val)
     return val;
 }
 
-#if defined(TARGET_PPC64)
-target_ulong helper_popcntb_64 (target_ulong val)
+target_ulong helper_popcntw (target_ulong val)
 {
-    val = (val & 0x5555555555555555ULL) + ((val >>  1) & 0x5555555555555555ULL);
-    val = (val & 0x3333333333333333ULL) + ((val >>  2) & 0x3333333333333333ULL);
-    val = (val & 0x0f0f0f0f0f0f0f0fULL) + ((val >>  4) & 0x0f0f0f0f0f0f0f0fULL);
+    val = (val & 0x55555555) + ((val >>  1) & 0x55555555);
+    val = (val & 0x33333333) + ((val >>  2) & 0x33333333);
+    val = (val & 0x0f0f0f0f) + ((val >>  4) & 0x0f0f0f0f);
+    val = (val & 0x00ff00ff) + ((val >>  8) & 0x00ff00ff);
+    val = (val & 0x0000ffff) + ((val >> 16) & 0x0000ffff);
     return val;
 }
 #endif
diff --git a/target-ppc/translate.c b/target-ppc/translate.c
index 4252508327..88681359c7 100644
--- a/target-ppc/translate.c
+++ b/target-ppc/translate.c
@@ -1483,13 +1483,21 @@ static void gen_xoris(DisasContext *ctx)
 /* popcntb : PowerPC 2.03 specification */
 static void gen_popcntb(DisasContext *ctx)
 {
+    gen_helper_popcntb(cpu_gpr[rA(ctx->opcode)], cpu_gpr[rS(ctx->opcode)]);
+}
+
+static void gen_popcntw(DisasContext *ctx)
+{
+    gen_helper_popcntw(cpu_gpr[rA(ctx->opcode)], cpu_gpr[rS(ctx->opcode)]);
+}
+
 #if defined(TARGET_PPC64)
-    if (ctx->sf_mode)
-        gen_helper_popcntb_64(cpu_gpr[rA(ctx->opcode)], cpu_gpr[rS(ctx->opcode)]);
-    else
-#endif
-        gen_helper_popcntb(cpu_gpr[rA(ctx->opcode)], cpu_gpr[rS(ctx->opcode)]);
+/* popcntd: PowerPC 2.06 specification */
+static void gen_popcntd(DisasContext *ctx)
+{
+    gen_helper_popcntd(cpu_gpr[rA(ctx->opcode)], cpu_gpr[rS(ctx->opcode)]);
 }
+#endif
 
 #if defined(TARGET_PPC64)
 /* extsw & extsw. */
@@ -8226,7 +8234,9 @@ GEN_HANDLER(oris, 0x19, 0xFF, 0xFF, 0x00000000, PPC_INTEGER),
 GEN_HANDLER(xori, 0x1A, 0xFF, 0xFF, 0x00000000, PPC_INTEGER),
 GEN_HANDLER(xoris, 0x1B, 0xFF, 0xFF, 0x00000000, PPC_INTEGER),
 GEN_HANDLER(popcntb, 0x1F, 0x03, 0x03, 0x0000F801, PPC_POPCNTB),
+GEN_HANDLER(popcntw, 0x1F, 0x1A, 0x0b, 0x0000F801, PPC_POPCNTWD),
 #if defined(TARGET_PPC64)
+GEN_HANDLER(popcntd, 0x1F, 0x1A, 0x0F, 0x0000F801, PPC_POPCNTWD),
 GEN_HANDLER(cntlzd, 0x1F, 0x1A, 0x01, 0x00000000, PPC_64B),
 #endif
 GEN_HANDLER(rlwimi, 0x14, 0xFF, 0xFF, 0x00000000, PPC_INTEGER),