@database "68040"
@master "VIF:Mu/MuManual/Autodocs/68040.doc"

@Node Main "68040.doc"
    @{" --Background-- " Link "--Background--"}
    @{" FPUControl() " Link "FPUControl()"}
@EndNode

@Node "--Background--" "68040.library/--Background--"

@{b}    PURPOSE@{ub}

	This is the support library for 68040 based Amigas. Its purposes
	are manifold:

	- Fixes and workarounds for several programs that typically appear
	  on 68040 based systems, mainly cache related.
	- Replacement functions for exec.library CPU related functions.
	- Loading and initialization of the FPSP68040 motorola software
	  module for emulation of FPU instructions not natively supported
	  by the 68040 internal FPU.
	- Setup of the 68040 MMU and related functions of the exec library.
	
	The last step is not done by the 68040.library directly but by the
	mmu.library which is loaded by the 68040.library on startup.

	Furthermore, this library provides user-callable functions. However,
	even though they are documented, they shouldn't be called directly.
	The recommended calling mechanism is not by using this library 
	directly, but by calling the same vector of the 680x0.library which
	does the same independent of the CPU installed in your system.

@EndNode

@Node "FPUControl()" "68040.library/FPUControl"

@{b}    NAME@{ub}
	FPUControl      -   control the generation of FPU exceptions

@{b}    SYNOPSIS@{ub}
	oldflags = FPUControl ( flags , mask );
	d0			 d0      d1

	ULONG FPUControl ( ULONG , ULONG );

@{b}    FUNCTION@{ub}
	This function disables or enables various exceptions the 68040
	FPU might generate. The purpose of this function is mainly to
	enable workarounds for badly written software.

@{b}    INPUTS@{ub}
	flags	-	A ULONG bit mask of the exceptions to disable. A
			set bit disables the corresponding exception.
	mask	-	A mask longword of the flags that are to be changed.
			A set bit indicates that the corresponding bit in
			flags mask is valid.

	The following bits are currently defined:

	FPUCtrlB_BSUN   0L      Disable the branch or set on unordered 
				exception.
	FPUCtrlB_INEX   1L      Disable the inexact result exception.
	FPUCtrlB_DIVZ   2L      Disable the divide by zero exception.
	FPUCtrlB_UNFL   3L      Disable the underflow exception.
	FPUCtrlB_OVFL   4L      Disable the overflow exception.
	FPUCtrlB_SNAN   5L      Disable the signalling NAN exception.
	FPUCtrlB_OPERR  6L      Disable the operand error.

@{b}    RESULTS@{ub}
	the old settings of the exception mask.

@{b}    NOTES@{ub}
	This function should not be called directly. It is called indirectly
	by the corresponding library function of the 680x0.library.

	This function does not alter the FPU status at all, it does not
	even touch the FPU. All it does is that it sets certain control
	bits in the 68040 library base which are interpreted by the
	exception vectors installed by this library.

	Therefore, this library vector does nothing if someone altered the
	FPU exception vectors manually.

@{b}    BUGS@{ub}

@{b}    SEE ALSO@{ub}
	libraries/68040.h, libraries/680x0.h,
	the Motorola 68040 manual.

@EndNode