ppc: implement xssubqp instruction

xssubqp: VSX Scalar Subtract Quad-Precision.

Signed-off-by: Jose Ricardo Ziviani <joserz@linux.vnet.ibm.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 34 insertions, 0 deletions

diff --git a/target/ppc/fpu_helper.c b/target/ppc/fpu_helper.c
index 5c34438d1d..48973a9db8 100644
--- a/target/ppc/fpu_helper.c
+++ b/target/ppc/fpu_helper.c
@@ -3430,3 +3430,37 @@ void helper_xssqrtqp(CPUPPCState *env, uint32_t opcode)
     putVSR(rD(opcode) + 32, &xt, env);
     float_check_status(env);
 }
+
+void helper_xssubqp(CPUPPCState *env, uint32_t opcode)
+{
+    ppc_vsr_t xt, xa, xb;
+    float_status tstat;
+
+    getVSR(rA(opcode) + 32, &xa, env);
+    getVSR(rB(opcode) + 32, &xb, env);
+    getVSR(rD(opcode) + 32, &xt, env);
+    helper_reset_fpstatus(env);
+
+    if (unlikely(Rc(opcode) != 0)) {
+        /* TODO: Support xssubqp after round-to-odd is implemented */
+        abort();
+    }
+
+    tstat = env->fp_status;
+    set_float_exception_flags(0, &tstat);
+    xt.f128 = float128_sub(xa.f128, xb.f128, &tstat);
+    env->fp_status.float_exception_flags |= tstat.float_exception_flags;
+
+    if (unlikely(tstat.float_exception_flags & float_flag_invalid)) {
+        if (float128_is_infinity(xa.f128) && float128_is_infinity(xb.f128)) {
+            float_invalid_op_excp(env, POWERPC_EXCP_FP_VXISI, 1);
+        } else if (float128_is_signaling_nan(xa.f128, &tstat) ||
+                   float128_is_signaling_nan(xb.f128, &tstat)) {
+            float_invalid_op_excp(env, POWERPC_EXCP_FP_VXSNAN, 1);
+        }
+    }
+
+    helper_compute_fprf_float128(env, xt.f128);
+    putVSR(rD(opcode) + 32, &xt, env);
+    float_check_status(env);
+}