sim: bfin: handle odd shift values with shift insns

The shift magnitude is a 5-bit signed value.  When it is between 0 and
15, then we do the requested shift, but when it is outside of that, we
have to do the opposite.

That means we flip between lshift and ashiftrt to match the hardware.

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

diff --git a/sim/bfin/ChangeLog b/sim/bfin/ChangeLog
index ffd9ff2..c702981 100644 (file)
--- a/sim/bfin/ChangeLog
+++ b/sim/bfin/ChangeLog
@@ -1,5 +1,12 @@
 2011-06-18  Robin Getz  <robin.getz@analog.com>
 
+       * bfin-sim.c (decode_dsp32shiftimm_0): With left shift vector insns,
+       call lshift only when count is positive.  Otherwise, call ashiftrt.
+       With arithmetic right shift insns, call ashiftrt when the value is
+       small enough, otherwise call lshift.
+
+2011-06-18  Robin Getz  <robin.getz@analog.com>
+
        * bfin-sim.c (extract_mult): Call saturate_s16 directly when
        mmod is M_IH rather than computing the result by hand.
 

diff --git a/sim/bfin/bfin-sim.c b/sim/bfin/bfin-sim.c
index 38e5fe1..11eea3a 100644 (file)
--- a/sim/bfin/bfin-sim.c
+++ b/sim/bfin/bfin-sim.c
@@ -5678,7 +5678,10 @@ decode_dsp32shiftimm_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1)
          TRACE_INSN (cpu, "R%i.%c = R%i.%c >>> %i;",
                      dst0, (HLs & 2) ? 'H' : 'L',
                      src1, (HLs & 1) ? 'H' : 'L', newimmag);
-         result = ashiftrt (cpu, in, newimmag, 16);
+         if (newimmag > 16)
+           result = lshift (cpu, in, 16 - (newimmag & 0xF), 16, 0);
+         else
+           result = ashiftrt (cpu, in, newimmag, 16);
        }
       else if (sop == 1 && bit8 == 0)
        {
@@ -5786,9 +5789,18 @@ decode_dsp32shiftimm_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1)
       bu32 astat;
 
       TRACE_INSN (cpu, "R%i = R%i << %i (V,S);", dst0, src1, count);
-      val0 = lshift (cpu, val0, count, 16, 1);
-      astat = ASTAT;
-      val1 = lshift (cpu, val1, count, 16, 1);
+      if (count >= 0)
+       {
+         val0 = lshift (cpu, val0, count, 16, 1);
+         astat = ASTAT;
+         val1 = lshift (cpu, val1, count, 16, 1);
+       }
+      else
+       {
+         val0 = ashiftrt (cpu, val0, -count, 16);
+         astat = ASTAT;
+         val1 = ashiftrt (cpu, val1, -count, 16);
+       }
       SET_ASTAT (ASTAT | astat);
 
       STORE (DREG (dst0), (val0 << 16) | val1);
@@ -5833,9 +5845,19 @@ decode_dsp32shiftimm_0 (SIM_CPU *cpu, bu16 iw0, bu16 iw1)
       TRACE_INSN (cpu, "R%i = R%i >>> %i %s;", dst0, src1, count,
                  sop == 0 ? "(V)" : "(V,S)");
 
-      val0 = ashiftrt (cpu, val0, count, 16);
-      astat = ASTAT;
-      val1 = ashiftrt (cpu, val1, count, 16);
+      if (count & 0x10)
+       {
+         val0 = lshift (cpu, val0, 16 - (count & 0xF), 16, 0);
+         astat = ASTAT;
+         val1 = lshift (cpu, val1, 16 - (count & 0xF), 16, 0);
+       }
+      else
+       {
+         val0 = ashiftrt (cpu, val0, count, 16);
+         astat = ASTAT;
+         val1 = ashiftrt (cpu, val1, count, 16);
+       }
+
       SET_ASTAT (ASTAT | astat);
 
       STORE (DREG (dst0), REG_H_L (val1 << 16, val0));