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x87 fix

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This commit is contained in:
Stanislav Shwartsman 2009-04-27 17:58:17 +00:00
parent 89f057ae7b
commit 321532efac
1 changed files with 20 additions and 8 deletions
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28
bochs/fpu/ferr.cc
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@ -1,5 +1,5 @@
/////////////////////////////////////////////////////////////////////////
// $Id: ferr.cc,v 1.15 2009-02-08 17:29:34 sshwarts Exp $
// $Id: ferr.cc,v 1.16 2009-04-27 17:58:17 sshwarts Exp $
/////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2003 Stanislav Shwartsman
@ -54,11 +54,13 @@ void BX_CPU_C::FPU_stack_underflow(int stnr, int pop_stack)
}
/* Returns unmasked exceptions if occured */
unsigned BX_CPU_C::FPU_exception(unsigned exception, bx_bool is_mem)
unsigned BX_CPU_C::FPU_exception(unsigned exception, bx_bool is_store)
{
/* Extract only the bits which we use to set the status word */
exception &= (FPU_SW_Exceptions_Mask);
Bit32u status = FPU_PARTIAL_STATUS;
/* Set the corresponding exception bits */
FPU_PARTIAL_STATUS |= exception;
@ -81,12 +83,22 @@ unsigned BX_CPU_C::FPU_exception(unsigned exception, bx_bool is_mem)
// written to the destination.
unmasked &= ~FPU_CW_Precision;
// If unmasked overflow or underflow occurs and destination is a memory
// location, the TOS and destination operands remain unchanged and no
// result is stored in the memory. If the destination is in the register
// stack, adjusted resulting value is stored in the destination operand.
if (! is_mem)
unmasked &= ~(FPU_CW_Underflow | FPU_CW_Overflow);
if (unmasked & (FPU_CW_Underflow | FPU_CW_Overflow)) {
// If unmasked over- or underflow occurs and dest is a memory location:
// - the TOS and destination operands remain unchanged
// - the inexact-result condition is not reported and C1 flag is cleared
// - no result is stored in the memory
// If the destination is in the register stack, adjusted resulting value
// is stored in the destination operand.
if (! is_store) {
unmasked &= ~(FPU_CW_Underflow | FPU_CW_Overflow);
}
else {
FPU_PARTIAL_STATUS &= ~FPU_SW_C1; // clear C1 flag
if (! (status & FPU_CW_Precision))
FPU_PARTIAL_STATUS &= ~FPU_CW_Precision;
}
}
return unmasked;
}