diff --git a/target/ppc/translate.c b/target/ppc/translate.c
index eba83efbbd..e083082814 100644
--- a/target/ppc/translate.c
+++ b/target/ppc/translate.c
@@ -827,7 +827,11 @@ static inline void gen_op_arith_compute_ca32(DisasContext *ctx,
     }
 
     t0 = tcg_temp_new();
-    tcg_gen_xor_tl(t0, arg0, arg1);
+    if (sub) {
+        tcg_gen_eqv_tl(t0, arg0, arg1);
+    } else {
+        tcg_gen_xor_tl(t0, arg0, arg1);
+    }
     tcg_gen_xor_tl(t0, t0, res);
     tcg_gen_extract_tl(cpu_ca32, t0, 32, 1);
     tcg_temp_free(t0);
@@ -1378,17 +1382,22 @@ static inline void gen_op_arith_subf(DisasContext *ctx, TCGv ret, TCGv arg1,
             tcg_temp_free(t1);
             tcg_gen_shri_tl(cpu_ca, cpu_ca, 32);    /* extract bit 32 */
             tcg_gen_andi_tl(cpu_ca, cpu_ca, 1);
+            if (is_isa300(ctx)) {
+                tcg_gen_mov_tl(cpu_ca32, cpu_ca);
+            }
         } else if (add_ca) {
             TCGv zero, inv1 = tcg_temp_new();
             tcg_gen_not_tl(inv1, arg1);
             zero = tcg_const_tl(0);
             tcg_gen_add2_tl(t0, cpu_ca, arg2, zero, cpu_ca, zero);
             tcg_gen_add2_tl(t0, cpu_ca, t0, cpu_ca, inv1, zero);
+            gen_op_arith_compute_ca32(ctx, t0, inv1, arg2, 0);
             tcg_temp_free(zero);
             tcg_temp_free(inv1);
         } else {
             tcg_gen_setcond_tl(TCG_COND_GEU, cpu_ca, arg2, arg1);
             tcg_gen_sub_tl(t0, arg2, arg1);
+            gen_op_arith_compute_ca32(ctx, t0, arg1, arg2, 1);
         }
     } else if (add_ca) {
         /* Since we're ignoring carry-out, we can simplify the