target-ppc: emulate cmpb instruction

Needed for Power ISA version 2.05 compliance.
Reviewed-by: NRichard Henderson <rth@twiddle.net>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>
Signed-off-by: NAlexander Graf <agraf@suse.de>

target-ppc/helper.h

@@ -36,6 +36,7 @@ DEF_HELPER_3(mulldo, i64, env, i64, i64)
 DEF_HELPER_FLAGS_1(cntlzw, TCG_CALL_NO_RWG_SE, tl, tl)
 DEF_HELPER_FLAGS_1(popcntb, TCG_CALL_NO_RWG_SE, tl, tl)
 DEF_HELPER_FLAGS_1(popcntw, TCG_CALL_NO_RWG_SE, tl, tl)
+DEF_HELPER_FLAGS_2(cmpb, TCG_CALL_NO_RWG_SE, tl, tl, tl)
 DEF_HELPER_3(sraw, tl, env, tl, tl)
 #if defined(TARGET_PPC64)
 DEF_HELPER_FLAGS_1(cntlzd, TCG_CALL_NO_RWG_SE, tl, tl)

target-ppc/int_helper.c

@@ -53,6 +53,21 @@ target_ulong helper_cntlzd(target_ulong t)
 }
 #endif
 
+target_ulong helper_cmpb(target_ulong rs, target_ulong rb)
+{
+    target_ulong mask = 0xff;
+    target_ulong ra = 0;
+    int i;
+
+    for (i = 0; i < sizeof(target_ulong); i++) {
+        if ((rs & mask) == (rb & mask)) {
+            ra |= mask;
+        }
+        mask <<= 8;
+    }
+    return ra;
+}
+
 /* shift right arithmetic helper */
 target_ulong helper_sraw(CPUPPCState *env, target_ulong value,
                          target_ulong shift)

target-ppc/translate.c

@@ -739,6 +739,13 @@ static void gen_isel(DisasContext *ctx)
     tcg_temp_free_i32(t0);
 }
 
+/* cmpb: PowerPC 2.05 specification */
+static void gen_cmpb(DisasContext *ctx)
+{
+    gen_helper_cmpb(cpu_gpr[rA(ctx->opcode)], cpu_gpr[rS(ctx->opcode)],
+                    cpu_gpr[rB(ctx->opcode)]);
+}
+
 /***                           Integer arithmetic                          ***/
 
 static inline void gen_op_arith_compute_ov(DisasContext *ctx, TCGv arg0,
@@ -8463,6 +8470,7 @@ GEN_HANDLER(cmp, 0x1F, 0x00, 0x00, 0x00400000, PPC_INTEGER),
 GEN_HANDLER(cmpi, 0x0B, 0xFF, 0xFF, 0x00400000, PPC_INTEGER),
 GEN_HANDLER(cmpl, 0x1F, 0x00, 0x01, 0x00400000, PPC_INTEGER),
 GEN_HANDLER(cmpli, 0x0A, 0xFF, 0xFF, 0x00400000, PPC_INTEGER),
+GEN_HANDLER_E(cmpb, 0x1F, 0x1C, 0x0F, 0x00000001, PPC_NONE, PPC2_ISA205),
 GEN_HANDLER(isel, 0x1F, 0x0F, 0xFF, 0x00000001, PPC_ISEL),
 GEN_HANDLER(addi, 0x0E, 0xFF, 0xFF, 0x00000000, PPC_INTEGER),
 GEN_HANDLER(addic, 0x0C, 0xFF, 0xFF, 0x00000000, PPC_INTEGER),