singrdk/base/Kernel/Native/arm/Crt/basic_f.asm

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2008-11-17 18:29:00 -05:00
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;
;;; Microsoft Research Singularity
;;;
;;; Copyright (c) Microsoft Corporation. All rights reserved.
;;;
;;; This file contains ARM-specific assembly code.
;;;
; basic_f.s
;
; Copyright (C) Advanced RISC Machines Limited, 1994. All rights reserved.
;
; RCS Revision: 1
; Checkin Date: 2007/06/29 02:59:16
; Revising Author
; Basic floating point functions
;
; Fixed == and != compares to be IEEE-754 compliant when input QNaNs.
; No exceptions are raised when only QNaNs are the only NaNs input to
; == and !=. Moved NaN detection and exception raising here.
; Removed unnecessary macros for compares that return results in flags.
; Added WindowsCE SEH mechanism support.
; Renamed routines.
;
LOC_SIZE EQU 0x18
OrgOp1l EQU 0x14
OrgOp2l EQU 0x10
ExDResl EQU 0x08
ExOp2l EQU 0x00
NewResl EQU 0x10
GET fpe.asm
GET kxarm.inc
;This code is very similar to the "double" versions. The documentation isn't
;extensively repeated. Refer to basic_d.s for further documentation.
;==============================================================================
; Compare.
;
; Timing:
; Flags: 7 (pos), 11 (false NaN), 9 (neg), 13 (false NaN) SA1.1 cycles
; Others: 9 / 13 / 11 / 15
;==============================================================================
MACRO
CmpReturn $cc
MOV a1, #0
MOV$cc a1, #1
ADD sp, sp, #LOC_SIZE
IF Interworking :LOR: Thumbing
LDMFD sp!, {lr}
BX lr
ELSE
LDMFD sp!, {pc}
ENDIF
MEND
MACRO
$lab FloatCompare $cc, $NaN_lab
ASSERT "$cc"="LO":LOR:"$cc"="LS":LOR:"$cc"="HS":LOR:"$cc"="HI":LOR:"$cc"="EQ":LOR:"$cc"="NE"
NESTED_ENTRY $lab
EnterWithLR_16
STMFD sp!, {lr} ; Save return address
SUB sp, sp, #LOC_SIZE ; Allocate local storage
PROLOG_END
ORRS tmp, fOP1, fOP2 ; separate into opnd1/2 both positive, or one negative
BMI $lab._negative
CMN tmp, #1 << 23 ; check whether operands might be infinite/NaN
BMI $lab._NaN_check_pos
CMP fOP1, fOP2
CmpReturn $cc
$lab._NaN_check_pos ; opnd1/2 might be inf/NaNs - now do the real check
CMN fOP1, #1 << 23 ; these get about 9% false hits - overhead 4 cycles
CMNPL fOP2, #1 << 23
BMI $lab._Inf_or_NaN_pos
$lab._cmp_pos
CMP fOP1, fOP2
CmpReturn $cc
$lab._Inf_or_NaN_pos ; at least one operand infinite or NaN - filter out infinities
MOV tmp, #1 << 24
CMN tmp, fOP1, LSL #1
CMNLS tmp, fOP2, LSL #1
BLS $lab._cmp_pos ; no NaN - continue compare
B $NaN_lab
$lab._negative ; at least one negative operand
CMN tmp, #1 << 23
BPL $lab._NaN_check_neg
MOVS tmp, tmp, LSL #1 ; check -0 == 0 (CS & EQ -> HS and LS)
CMPNE fOP2, fOP1
CmpReturn $cc
$lab._NaN_check_neg ; opnd1/2 might be inf/NaNs - now do the real check
MOV tmp, #1 << 24 ; these get about 9% false hits - overhead 4 cycles
CMN tmp, fOP1, LSL #1
CMNLS tmp, fOP2, LSL #1
BHI $NaN_lab
CMP fOP2, fOP1 ; -0 == 0 check not needed...
CmpReturn $cc
MEND
;==============================================================================
;Invalid Operation checking (NaNs on compares)
;;
IMPORT FPE_Raise
;;
;; NANs on compares <, >, <=, and >=
;;
;; SNANs and QNANs both raise the invalid operation exception, so we don't
;; care which kind of NAN we get. This is because if we get an SNAN or SNANs,
;; we raise the invalid operation exception. If we get a QNAN or QNANs, we
;; have an unordered compare and must also raise the invalid operation
;; exception.
;;
;; Register usage on entry:
;; r0 - Arg1
;; r1 - Arg2
;; r14 - available for scratch
;; All others have normal usage semantics.
;;
MACRO
$l FCmpNaN $Filter_lab
$l STR r1, [sp, #ExOp2l] ;; Push Arg2
MOV r3, #_FpCompareUnordered ;; Load default result
STR r3, [sp, #ExDResl] ;; Push default result
MOV r2, r0 ;; Arg1
MOV r1, #IVO_bit ;; ExInfo: InvalidOp,
ORR r1, r1, #_FpCmpS ;; float compare
ADD r0, sp, #NewResl ;; Pointer to result
CALL FPE_Raise ;; Deal with exception information
IF Thumbing :LAND: :LNOT: Interworking
CODE16
bx pc ; switch back to ARM mode
nop
CODE32
ENDIF
LDR r0, [sp, #NewResl] ;; Load return value
ADD sp, sp, #LOC_SIZE ;; Retore stack
;;
;; Register usage:
;;
;; r0 - Result from exception handler
;;
;; We must now examine the result from the exception handler and change it
;; to TRUE or FALSE, depending on the operation. After changing the result,
;; we return to the caller of the FP double compare routine.
;;
B $Filter_lab
MEND
;;
;; NANs on compares == and !=
;;
;; SNANs and QNANs are treated differently for == and !=. If we get an SNAN
;; or SNANs, we must raise the invalid operation exception. If we only have
;; a QNAN or QNANs, then we simply return false and true for == and !=,
;; respectively. Unordered comparisions for == and != do not raise the
;; invalid operation exception.
;;
;; Register usage on entry:
;; r0 - Arg1
;; r1 - Arg2
;; r14 - available for scratch
;; All others have normal usage semantics.
;;
MACRO
$l FCmpSNaN $Filter_lab
$l MOV r14, r0, LSL #1 ;; Extract exponent from Arg1
MOV r14, r14, LSR #24 ;; ...
CMP r14, #0xFF ;; Arg1.exponent == 0xFF?
BNE $l.checkArg2 ;; Arg1 not a NaN so check Arg2
MOVS r14, r0, LSL #9 ;; Arg1.Mantissa bits set?
BEQ $l.checkArg2 ;; Arg1 not a NaN so check Arg2
TST r0, #fSignalBit ;; Check if SNAN
BEQ $l.SNaN ;; If high mant. bit clear, SNaN
$l.checkArg2
MOV r14, r1, LSL #1 ;; Extract exponent from Arg2
MOV r14, r14, LSR #24 ;; ...
CMP r14, #0xFF ;; Arg2.exponent == 0xFF?
BNE $l.cmpUnordered ;; Arg2 not a NaN so Arg1 is a QNaN
MOVS r14, r1, LSL #9 ;; Arg2.Mantissa bits set?
BEQ $l.cmpUnordered ;; Arg2 not a NaN so Arg1 is a QNaN
TST r1, #fSignalBit ;; Check if SNAN
BEQ $l.SNaN ;; If high mant. bit clear, SNaN
$l.cmpUnordered
MOV r0, #_FpCompareUnordered ;; Have an unordered compare so
B $Filter_lab ;; don't raise an exception
$l.SNaN
STR r1, [sp, #ExOp2l] ;; Push Arg2
MOV r3, #_FpCompareUnordered ;; Load default result
STR r3, [sp, #ExDResl] ;; Push default result
MOV r2, r0 ;; Arg1
MOV r1, #IVO_bit ;; ExInfo: InvalidOp,
ORR r1, r1, #_FpCmpS ;; float compare
ADD r0, sp, #NewResl ;; Pointer to result
CALL FPE_Raise ;; Deal with exception information
IF Thumbing :LAND: :LNOT: Interworking
CODE16
bx pc ; switch back to ARM mode
nop
CODE32
ENDIF
LDR r0, [sp, #NewResl] ;; Load return value
;;
;; Register usage:
;;
;; r0 - Result from exception handler
;;
;; We must now examine the result from the exception handler and change it
;; to TRUE or FALSE, depending on the operation. After changing the result,
;; we return to the caller of the FP double compare routine.
;;
B $Filter_lab
MEND
;==============================================================================
; Equality
[ :DEF: eq_s
Export __eqs
AREA |.text|, CODE, READONLY
__eqs FloatCompare EQ, __eqs_NaN
__eqs_NaN FCmpSNaN __eqs_Filter
__eqs_Filter
CMP r0, #_FpCompareEqual ;; Check if compared ==
MOVEQ r0, #1 ;; If did, return true
MOVNE r0, #0 ;; else return false
ADD sp, sp, #0x18 ;; Pop extra arg passing space
IF Interworking :LOR: Thumbing
LDMIA sp!, {lr} ;; Return
BX lr
ELSE
LDMIA sp!, {pc} ;; Return
ENDIF
ENTRY_END __eqs
]
;==============================================================================
;Inequality
[ :DEF: neq_s
Export __nes
AREA |.text|, CODE, READONLY
__nes FloatCompare NE, __nes_NaN
__nes_NaN FCmpSNaN __nes_Filter
__nes_Filter
CMP r0, #_FpCompareEqual ;; Check if compared ==
MOVEQ r0, #0 ;; If did, return false
MOVNE r0, #1 ;; else return true
ADD sp, sp, #0x18 ;; Pop extra arg passing space
IF Interworking :LOR: Thumbing
LDMIA sp!, {lr} ;; Return
BX lr
ELSE
LDMIA sp!, {pc} ;; Return
ENDIF
ENTRY_END __nes
]
;==============================================================================
;Less Than
[ :DEF: ls_s
Export __lts
AREA |.text|, CODE, READONLY
__lts FloatCompare LO, __lts_NaN
__lts_NaN FCmpNaN __lts_Filter
__lts_Filter
CMP r0, #_FpCompareLess ;; Check if compared <
MOVEQ r0, #1 ;; If did, return true
MOVNE r0, #0 ;; else return false
IF Interworking :LOR: Thumbing
LDMIA sp!, {lr} ;; Return
BX lr
ELSE
LDMIA sp!, {pc} ;; Return
ENDIF
ENTRY_END __lts
]
;==============================================================================
;Less Than or Equal
[ :DEF: leq_s
Export __les
AREA |.text|, CODE, READONLY
__les FloatCompare LS, __les_NaN
__les_NaN FCmpNaN __les_Filter
__les_Filter
CMP r0, #_FpCompareLess ;; Check if compared <
MOVEQ r0, #1 ;; If did,
BEQ __les_Filter_end ;; return true
CMP r0, #_FpCompareEqual ;; Check if compared ==
MOVEQ r0, #1 ;; If did, return true
MOVNE r0, #0 ;; else return false
__les_Filter_end
IF Interworking :LOR: Thumbing
LDMIA sp!, {lr} ;; Return
BX lr
ELSE
LDMIA sp!, {pc} ;; Return
ENDIF
ENTRY_END __les
]
;==============================================================================
;Greater Than
[ :DEF: gr_s
Export __gts
AREA |.text|, CODE, READONLY
__gts FloatCompare HI, __gts_NaN
__gts_NaN FCmpNaN __gts_Filter
__gts_Filter
CMP r0, #_FpCompareGreater ;; Check if compared >
MOVEQ r0, #1 ;; If did, return true
MOVNE r0, #0 ;; else return false
IF Interworking :LOR: Thumbing
LDMIA sp!, {lr} ;; Return
BX lr
ELSE
LDMIA sp!, {pc} ;; Return
ENDIF
ENTRY_END __gts
]
;==============================================================================
;Greater Than or Equal
[ :DEF: geq_s
Export __ges
AREA |.text|, CODE, READONLY
__ges FloatCompare HS, __ges_NaN
__ges_NaN FCmpNaN __ges_Filter
__ges_Filter
CMP r0, #_FpCompareGreater ;; Check if compared >
MOVEQ r0, #1 ;; If did,
BEQ __ges_Filter_end ;; return true
CMP r0, #_FpCompareEqual ;; Check if compared ==
MOVEQ r0, #1 ;; If did, return true
MOVNE r0, #0 ;; else return false
__ges_Filter_end
IF Interworking :LOR: Thumbing
LDMIA sp!, {lr} ;; Return
BX lr
ELSE
LDMIA sp!, {pc} ;; Return
ENDIF
ENTRY_END __ges
]
;==============================================================================
END