ppc: Use FPSCR defines instead of constants

There are FPSCR-related defines in target/ppc/cpu.h which can be used in
place of constants and explicit shifts which arguably improve the code a
bit in places.

Signed-off-by: Paul A. Clarke <pc@us.ibm.com>
Message-Id: <1568817169-1721-1-git-send-email-pc@us.ibm.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
diff --git a/target/ppc/dfp_helper.c b/target/ppc/dfp_helper.c
index da8e08a..7533991 100644
--- a/target/ppc/dfp_helper.c
+++ b/target/ppc/dfp_helper.c
@@ -220,8 +220,8 @@
     default:
         assert(0); /* should never get here */
     }
-    dfp->env->fpscr &= ~(0x1F << 12);
-    dfp->env->fpscr |= (fprf << 12);
+    dfp->env->fpscr &= ~FP_FPRF;
+    dfp->env->fpscr |= (fprf << FPSCR_FPRF);
 }
 
 static void dfp_set_FPRF_from_FRT(struct PPC_DFP *dfp)
@@ -369,8 +369,8 @@
 
 static void dfp_set_FPCC_from_CRBF(struct PPC_DFP *dfp)
 {
-    dfp->env->fpscr &= ~(0xF << 12);
-    dfp->env->fpscr |= (dfp->crbf << 12);
+    dfp->env->fpscr &= ~FP_FPCC;
+    dfp->env->fpscr |= (dfp->crbf << FPSCR_FPCC);
 }
 
 static inline void dfp_makeQNaN(decNumber *dn)