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windwakr



Joined: 30 Jun 2004
Posts: 827
Location: Michigan, USA
windwakr
I dont know where to put this, so I'll put it here.

If I modify the control word on the fpu, does it go back to the default setting the next time finit is called? Question

Info on control word.

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Post 14 Jul 2008, 21:42
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LocoDelAssembly
Your code has a bug


Joined: 06 May 2005
Posts: 4633
Location: Argentina
LocoDelAssembly
Intel® 64 and IA-32 Architectures Software Developer’s Manual -- Volume 2A: Instruction Set Reference, A-M wrote:
Description
Sets the FPU control, status, tag, instruction pointer, and data pointer registers to
their default states. The FPU control word is set to 037FH (round to nearest, all
exceptions masked, 64-bit precision). The status word is cleared (no exception flags
set, TOP is set to 0). The data registers in the register stack are left unchanged, but
they are all tagged as empty (11B). Both the instruction and data pointers are
cleared.
The FINIT instruction checks for and handles any pending unmasked floating-point
exceptions before performing the initialization; the FNINIT instruction does not.
The assembler issues two instructions for the FINIT instruction (an FWAIT instruction
followed by an FNINIT instruction), and the processor executes each of these instructions
in separately. If an exception is generated for either of these instructions, the
save EIP points to the instruction that caused the exception.
This instruction’s operation is the same in non-64-bit modes and 64-bit mode.
Post 14 Jul 2008, 22:06
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windwakr



Joined: 30 Jun 2004
Posts: 827
Location: Michigan, USA
windwakr
thank you
Post 14 Jul 2008, 22:15
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