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/* $OpenBSD: m88110_fp.S,v 1.3 2007/12/02 21:32:08 miod Exp $ */
/*
* Copyright (c) 2007, Miodrag Vallat.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice, this permission notice, and the disclaimer below
* appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include "assym.h"
#include <machine/asm.h>
#include <machine/trap.h>
/* FPECR bits */
#define FIOV_BIT 7
#define FUNIMP_BIT 6
#define FPRV_BIT 5
#define FROP_BIT 4
#define FDVZ_BIT 3
#define FUNF_BIT 2
#define FOVF_BIT 1
#define FINX_BIT 0
/* FPSR and FPCR exception bits */
#define EFINV_BIT 4
#define EFDVZ_BIT 3
#define EFUNF_BIT 2
#define EFOVF_BIT 1
#define EFINX_BIT 0
ASENTRY(m88110_fpu_exception)
/*
* On entry, r30 point to the exception frame.
* Save our guts so that we can call other functions.
*/
subu r31, r31, 16
st r1, r31, 0
st r30, r31, 4
/*
* We never saved the floating point exception and control
* registers. Do it now, and then decide what kind of exception
* we've got.
* Note that we can access the control registers even if the
* FPU is disabled.
*/
fldcr r2, FPECR
fldcr r3, FPSR
fldcr r4, FPCR
st r2, r30, EF_FPECR * 4
st r3, r30, EF_FPSR * 4
st r4, r30, EF_FPCR * 4
/*
* Check for floating point unimplemented bit first, as other
* bits are undefined if this bit is set.
*/
bb1 FUNIMP_BIT, r2, _ASM_LABEL(m88110_funimp)
/*
* Check for the other exceptions.
*
* FOVF and FUNF need to be checked before FINX.
*/
bb1 FIOV_BIT, r2, _ASM_LABEL(m88110_fiov)
bb1 FPRV_BIT, r2, _ASM_LABEL(m88110_fprv)
bb1 FROP_BIT, r2, _ASM_LABEL(m88110_frop)
bb1 FDVZ_BIT, r2, _ASM_LABEL(m88110_fdvz)
bb1 FUNF_BIT, r2, _ASM_LABEL(m88110_funf)
bb1 FOVF_BIT, r2, _ASM_LABEL(m88110_fovf)
bb1 FINX_BIT, r2, _ASM_LABEL(m88110_finx)
/*
* If control goes here, we got a floating point exception,
* but no cause bit is set. This shouldn't happen; if it does,
* just fall through the unimplemented instruction code.
*/
ASLOCAL(m88110_funimp)
/*
* Check if the fpu was enabled.
*/
ld r5, r30, EF_EPSR * 4
/* FPE_FLTINV */
bb1 PSR_FPU_DISABLE_BIT, r5, _ASM_LABEL(m88110_fpeflt)
/*
* We should check the faulting instruction here.
* This can be:
* - fsqrt (unimplemented)
* - any valid fp instruction operating on an odd register pair
* - any bogus fp instruction.
*/
/* XXX TBD */
br _ASM_LABEL(m88110_fpeflt)
/*
* Floating-point integer overflow.
*
* Register it in the status register, and if this exception is allowed
* in the control register, send a trap.
*/
ASLOCAL(m88110_fiov)
set r3, r3, 1<EFINV_BIT>
fstcr r3, FPSR
/* FPE_FLTSUB */
bb1 EFINV_BIT, r4, _ASM_LABEL(m88110_fpeflt)
jmp.n r1
addu r31, r31, 16
/*
* Floating-point privilege violation.
*
* This exception is caused by fldcr, fstcr or fxcr with either a
* non-existing register (fcr1-fcr61), or fcr0 from userland.
*/
ASLOCAL(m88110_fprv)
/* ILL_PRVREG */
or r2, r0, T_PRIVINFLT
bsr.n _C_LABEL(m88110_trap)
or r3, r0, r30
ld r1, r31, 0
jmp.n r1
addu r31, r31, 16
/*
* Floating-point reserved operand.
*/
ASLOCAL(m88110_frop)
set r3, r3, 1<EFINV_BIT>
fstcr r3, FPSR
/* XXX TBD lots of analysis to do here... */
/* FPE_FLTINV */
bb1 EFINV_BIT, r4, _ASM_LABEL(m88110_fpeflt)
/* XXX TBD ... and then decide on a value... */
jmp.n r1
addu r31, r31, 16
/*
* Floating-point divide by zero.
*
* Register it in the status register, and if this exception is allowed
* in the control register, send a trap.
*/
ASLOCAL(m88110_fdvz)
set r3, r3, 1<EFDVZ_BIT>
fstcr r3, FPSR
/* FPE_INTDIV */
bb1 EFDVZ_BIT, r4, _ASM_LABEL(m88110_fpeflt)
jmp.n r1
addu r31, r31, 16
/*
* Floating-point underflow.
*/
ASLOCAL(m88110_funf)
set r3, r3, 1<EFUNF_BIT>
set r3, r3, 1<EFINX_BIT>
fstcr r3, FPSR
/* FPE_FLTUND */
bb1 EFUNF_BIT, r4, _ASM_LABEL(m88110_fpeflt)
/* FPE_FLTRES */
bb1 EFINX_BIT, r4, _ASM_LABEL(m88110_fpeflt)
/* XXX TBD check rounding mode, check destination register, write
default value to it/them. */
jmp.n r1
addu r31, r31, 16
/*
* Floating-point overflow.
*/
ASLOCAL(m88110_fovf)
set r3, r3, 1<EFOVF_BIT>
set r3, r3, 1<EFINX_BIT>
fstcr r3, FPSR
/* FPE_FLTOVF */
bb1 EFOVF_BIT, r4, _ASM_LABEL(m88110_fpeflt)
/* FPE_FLTRES */
bb1 EFINX_BIT, r4, _ASM_LABEL(m88110_fpeflt)
/* XXX TBD check rounding mode, check destination register, write
default value to it/them. */
jmp.n r1
addu r31, r31, 16
/*
* Floating-point inexact.
*
* Register it in the status register, and if this exception is allowed
* in the control register, send a trap.
*/
ASLOCAL(m88110_finx)
set r3, r3, 1<EFINX_BIT>
fstcr r3, FPSR
/* FPE_FLTRES */
bb1 EFINX_BIT, r4, _ASM_LABEL(m88110_fpeflt)
jmp.n r1
addu r31, r31, 16
ASLOCAL(m88110_fpeflt)
or r2, r0, T_FPEPFLT
bsr.n _C_LABEL(m88110_trap)
or r3, r0, r30
ld r1, r31, 0
jmp.n r1
addu r31, r31, 16
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