fs_mul32.asm

MMI层OBJ不能完全编译

;******************************************************************************
;* FS_MUL.ASM  - 32 BIT STATE -  v2.54                                        *
;* Copyright (c) 1996-2004 Texas Instruments Incorporated                     *
;******************************************************************************

;****************************************************************************
;* F_MUL - MULTIPLY TWO IEEE 754 FORMAT SINGLE PRECISION FLOATING 
;* 	   POINT NUMBERS.
;****************************************************************************
;*
;*   o INPUT OP1 IS IN r0
;*   o INPUT OP2 IS IN r1
;*   o RESULT IS RETURNED IN r0
;*   o INPUT OP2 IN r1 IS NOT DESTROYED
;*
;*   o SIGNALLING NOT-A-NUMBER (SNaN) AND QUIET NOT-A-NUMBER (QNaN)
;*     ARE TREATED AS INFINITY
;*   o OVERFLOW RETURNS +/- INFINITY (0x7f800000/ff800000)
;*   o UNDERFLOW RETURNS ZERO (0x00000000)
;*   o DENORMALIZED NUMBERS ARE TREATED AS UNDERFLOWS
;*   o ROUNDING MODE:  ROUND TO NEAREST
;*
;*   o IF THE OPERATION INVOLVES INFINITY AS AN INPUT, UNLESS THE OTHER INPUT
;*     IS ZERO, THE RESULT IS INFINITY WITH THE SIGN DETERMINED IN THE USUAL
;*     FASHION.
;*
;****************************************************************************
;*
;* +--------------------------------------------------------------+
;* | SINGLE PRECISION FLOATING POINT FORMAT                       |
;* |								  |
;* |   31 30    23 22                    0			  |
;* |   +-+--------+-----------------------+			  |
;* |   |S|    E   |           M           +			  |
;* |   +-+--------+-----------------------+			  |
;* |								  |
;* |   <S>  SIGN FIELD    :        0 - POSITIVE VALUE		  |
;* |			           1 - NEGATIVE VALUE		  |
;* |								  |
;* |   <E>  EXPONENT FIELD:       00 - ZERO IFF M == 0		  |
;* |			     01...FE - EXPONENT VALUE (127 BIAS)  |
;* |				  FF - INFINITY			  |
;* |								  |
;* |   <M>  MANTISSA FIELD:  FRACTIONAL MAGNITUDE WITH IMPLIED 1  |
;* +--------------------------------------------------------------+
;*
;****************************************************************************
	.state32

	.global FS_MUL


in1	.set	r0
in2	.set	r1

m1	.set	r2
e1	.set	r3
m2	.set	r4
e2	.set	r5
sign	.set	r6
tmp	.set	lr

FS_MUL:	.asmfunc stack_usage(24)
	STMFD	sp!, {r2-r6, lr}

	EORS	sign, in1, in2		; SET THE SIGN OF THE RESULT
	MOVMI	sign, #0x80000000	;
	MOVPL	sign, #0x00000000	;

	MOV	m1, in1, LSL #8		; PUT INPUT #1 MANTISSA IN m1
	MOV	e1, in1, LSL #1		; PUT INPUT #1 EXPONENT IN e1
	MOVS	e1, e1, LSR #24		;
	ORRNE	m1, m1, #0x80000000	; SET IMPLIED ONE IN MANTISSA IF e1 != 0

	MOVEQ	in1, #0			; IF e1 == 0, THEN UNDERFLOW
	LDMEQFD	sp!, {r2-r6, pc}	;

	CMP	e1, #0xFF		; IF e1 == 0xFF, THEN OVERFLOW
	BEQ	ovfl			;

	MOV	m2, in2, LSL #8		; PUT INPUT #2 MANTISSA IN m2
	MOV	e2, in2, LSL #1		; PUT INPUT #2 EXPONENT IN e2
	MOVS	e2, e2, LSR #24		;
	ORRNE	m2, m2, #0x80000000	; SET IMPLIED ONE IN MANTISSA IF e2 != 0

	MOVEQ	in1, #0			; IF e2 == 0, THEN UNDERFLOW
	LDMEQFD	sp!, {r2-r6, pc}	;

	CMP	e2, #0xFF		; IF e2 == 0xFF, THEN OVERFLOW
	BEQ	ovfl			;

	ADD	e1, e1, e2		; ADD EXPONENTS

	UMULL	e2, m2, m1, m2		; MULTIPLY THE MANTISAE INTO m2:e2

	CMP	m2, #0			;
	MOVPL	m2, m2, LSL #1		; ADJUST THE EXPONENT AS NECESSARY
	SUBPL	e1, e1, #0x1		; AND ADJUST FOR BIAS

	ADDS	m2, m2, #0x00000080	; ADD 1/2 FOR ROUNDING
	ADDCS	e1, e1, #0x1		; AND ADJUST FOR OVERFLOW
	MOVCS	m2, m2, LSR #1		;

	SUBS	e1, e1, #0x00000007E	; ADJUST THE BIAS
	MOVLE	in1, #0			; AND CHECK FOR UNDERFLOW
	LDMLEFD	sp!, {r2-r6, pc}	;

	CMP	e1, #0x000000FF		; CHECK FOR EXPONENT OVERFLOW
	BCS	ovfl			;

	MOV	in1, m2, LSR #8		; SETUP THE MANTISSA
	BIC	in1, in1, #0x00800000	; REMOVE IMPLIED 1 IN MANTISSA
	ORR	in1, in1, e1, LSL #23	; REPACK THE EXPONENT INTO in1
	ORR	in1, in1, sign		; REPACK THE SIGN INTO in1
		
	LDMFD	sp!, {r2-r6, pc}	;

ovfl:	MOV	tmp, #0xFF		; OVERFLOW, RETURN +/- INFINITY
	MOV	tmp, tmp, LSL #23	; 
	ORR	in1, sign, tmp		;
	LDMFD	sp!, {r2-r6, pc}	;

	.endasmfunc

	.end