sim: bfin: handle AN (negative overflows) in dsp mult insns

The current dsp mult handler does not take care of overflows which turn
values negative (and thus set AN in ASTAT).  So implement it.

Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

1 files changed, 33 insertions, 8 deletions

diff --git a/sim/bfin/bfin-sim.c b/sim/bfin/bfin-sim.c
index 5df7340..ba0e0c2 100644
--- a/sim/bfin/bfin-sim.c
+++ b/sim/bfin/bfin-sim.c
@@ -1562,10 +1562,11 @@ extract_mult (SIM_CPU *cpu, bu64 res, int mmod, int MM,
 
 static bu32
 decode_macfunc (SIM_CPU *cpu, int which, int op, int h0, int h1, int src0,
-		int src1, int mmod, int MM, int fullword, bu32 *overflow)
+		int src1, int mmod, int MM, int fullword, bu32 *overflow,
+		bu32 *neg)
 {
   bu64 acc;
-  bu32 sat = 0, tsat;
+  bu32 sat = 0, tsat, ret;
 
   /* Sign extend accumulator if necessary, otherwise unsigned.  */
   if (mmod == 0 || mmod == M_T || mmod == M_IS || mmod == M_ISS2
@@ -1658,6 +1659,9 @@ decode_macfunc (SIM_CPU *cpu, int which, int op, int h0, int h1, int src0,
 	default:
 	  illegal_instruction (cpu);
 	}
+
+      if (acc & 0x8000000000ull)
+	*neg = 1;
     }
 
   STORE (AXREG (which), (acc >> 32) & 0xff);
@@ -1666,7 +1670,20 @@ decode_macfunc (SIM_CPU *cpu, int which, int op, int h0, int h1, int src0,
   if (sat)
     STORE (ASTATREG (avs[which]), sat);
 
-  return extract_mult (cpu, acc, mmod, MM, fullword, overflow);
+  ret = extract_mult (cpu, acc, mmod, MM, fullword, overflow);
+
+  if (!fullword)
+    {
+      if (ret & 0x8000)
+	*neg = 1;
+    }
+  else
+    {
+      if (ret & 0x80000000)
+	*neg = 1;
+    }
+
+  return ret;
 }
 
 bu32
@@ -3702,7 +3719,7 @@ decode_dsp32mac_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1)
   int h01  = ((iw1 >> DSP32Mac_h01_bits) & DSP32Mac_h01_mask);
 
   bu32 res = DREG (dst);
-  bu32 v_i = 0, zero = 0;
+  bu32 v_i = 0, zero = 0, n_1 = 0, n_0 = 0;
 
   static const char * const ops[] = { "=", "+=", "-=" };
   char _buf[128], *buf = _buf;
@@ -3727,7 +3744,7 @@ decode_dsp32mac_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1)
   if (w1 == 1 || op1 != 3)
     {
       bu32 res1 = decode_macfunc (cpu, 1, op1, h01, h11, src0,
-				  src1, mmod, MM, P, &v_i);
+				  src1, mmod, MM, P, &v_i, &n_1);
 
       if (w1)
 	buf += sprintf (buf, P ? "R%i" : "R%i.H", dst + P);
@@ -3773,7 +3790,7 @@ decode_dsp32mac_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1)
   if (w0 == 1 || op0 != 3)
     {
       bu32 res0 = decode_macfunc (cpu, 0, op0, h00, h10, src0,
-				  src1, mmod, 0, P, &v_i);
+				  src1, mmod, 0, P, &v_i, &n_0);
 
       if (w0)
 	buf += sprintf (buf, P ? "R%i" : "R%i.L", dst);
@@ -3822,8 +3839,16 @@ decode_dsp32mac_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1)
       if (v_i)
 	SET_ASTATREG (vs, v_i);
     }
-  if (op0 == 3 || op1 == 3)
-    SET_ASTATREG (az, zero);
+
+  if ((w0 == 1 && op0 == 3) || (w1 == 1 && op1 == 3))
+    {
+      SET_ASTATREG (az, zero);
+      if (!(w0 == 1 && op0 == 3))
+	n_0 = 0;
+      if (!(w1 == 1 && op1 == 3))
+	n_1 = 0;
+      SET_ASTATREG (an, n_1 | n_0);
+    }
 }
 
 static void