[Qemu-devel] Fwd: qemu-arm : additional fix around QSUB maybe need

[Paul Brook]

----------  Forwarded Message  ----------

Subject: qemu-arm : additional fix around QSUB maybe need
Date: Saturday 14 May 2005 02:26
From: "TAKAGO Daisuke" <address@hidden>
To: address@hidden

Dear Paul Brook

Hello!
Thank very much for sending fix-patch to me quickly!!
I noticed that patch applyed to CVS. Then I built qemu-arm from CVS.

I tested saturating instructions(QADD, QSUB).
QADD could execute saturating instruction, but QSUB cound not.
I found the problem points in  op_subl_T0_T1_saturate().

The following is a fix point I think.

----- qemu/op.c (near line 797)
void OPPROTO op_subl_T0_T1_saturate(void)
{
  uint32_t res;

  res = T0 - T1;
  if (((res ^ T0) & SIGNBIT) && ((T0 ^ T1) & SIGNBIT)) {
      env->QF = 1;
      if (T0 & SIGNBIT)
-          T0 = 0x8000000;
+          T0 = 0x80000000;
      else
          T0 = 0x7fffffff;
  }
  else
    T0 = res;

  FORCE_RET();
}
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