patch-1.3.94 linux/arch/m68k/fpsp040/sint.S

• Lines: 248
• Date: Sat Feb 24 22:58:44 1996
• Orig file: v1.3.93/linux/arch/m68k/fpsp040/sint.S
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.93/linux/arch/m68k/fpsp040/sint.S linux/arch/m68k/fpsp040/sint.S
@@ -0,0 +1,247 @@
+|
+|	sint.sa 3.1 12/10/90
+|
+|	The entry point sINT computes the rounded integer 
+|	equivalent of the input argument, sINTRZ computes 
+|	the integer rounded to zero of the input argument.
+|
+|	Entry points sint and sintrz are called from do_func
+|	to emulate the fint and fintrz unimplemented instructions,
+|	respectively.  Entry point sintdo is used by bindec.
+|
+|	Input: (Entry points sint and sintrz) Double-extended
+|		number X in the ETEMP space in the floating-point
+|		save stack.
+|	       (Entry point sintdo) Double-extended number X in
+|		location pointed to by the address register a0.
+|	       (Entry point sintd) Double-extended denormalized
+|		number X in the ETEMP space in the floating-point
+|		save stack.
+|
+|	Output: The function returns int(X) or intrz(X) in fp0.
+|
+|	Modifies: fp0.
+|
+|	Algorithm: (sint and sintrz)
+|
+|	1. If exp(X) >= 63, return X. 
+|	   If exp(X) < 0, return +/- 0 or +/- 1, according to
+|	   the rounding mode.
+|	
+|	2. (X is in range) set rsc = 63 - exp(X). Unnormalize the
+|	   result to the exponent $403e.
+|
+|	3. Round the result in the mode given in USER_FPCR. For
+|	   sintrz, force round-to-zero mode.
+|
+|	4. Normalize the rounded result; store in fp0.
+|
+|	For the denormalized cases, force the correct result
+|	for the given sign and rounding mode.
+|
+|		        Sign(X)
+|		RMODE   +    -
+|		-----  --------
+|		 RN    +0   -0
+|		 RZ    +0   -0
+|		 RM    +0   -1
+|		 RP    +1   -0
+|
+|
+|		Copyright (C) Motorola, Inc. 1990
+|			All Rights Reserved
+|
+|	THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF MOTOROLA 
+|	The copyright notice above does not evidence any  
+|	actual or intended publication of such source code.
+
+|SINT    idnt    2,1 | Motorola 040 Floating Point Software Package
+
+	|section	8
+
+	.include "fpsp.h"
+
+	|xref	dnrm_lp
+	|xref	nrm_set
+	|xref	round
+	|xref	t_inx2
+	|xref	ld_pone
+	|xref	ld_mone
+	|xref	ld_pzero
+	|xref	ld_mzero
+	|xref	snzrinx
+
+|
+|	FINT
+|
+	.global	sint
+sint:
+	bfextu	FPCR_MODE(%a6){#2:#2},%d1	|use user's mode for rounding
+|					;implicity has extend precision
+|					;in upper word. 
+	movel	%d1,L_SCR1(%a6)		|save mode bits
+	bras	sintexc			
+
+|
+|	FINT with extended denorm inputs.
+|
+	.global	sintd
+sintd:
+	btstb	#5,FPCR_MODE(%a6)
+	beq	snzrinx		|if round nearest or round zero, +/- 0
+	btstb	#4,FPCR_MODE(%a6)
+	beqs	rnd_mns
+rnd_pls:
+	btstb	#sign_bit,LOCAL_EX(%a0)
+	bnes	sintmz
+	bsr	ld_pone		|if round plus inf and pos, answer is +1
+	bra	t_inx2
+rnd_mns:
+	btstb	#sign_bit,LOCAL_EX(%a0)
+	beqs	sintpz
+	bsr	ld_mone		|if round mns inf and neg, answer is -1
+	bra	t_inx2
+sintpz:
+	bsr	ld_pzero
+	bra	t_inx2
+sintmz:
+	bsr	ld_mzero
+	bra	t_inx2
+
+|
+|	FINTRZ
+|
+	.global	sintrz
+sintrz:
+	movel	#1,L_SCR1(%a6)		|use rz mode for rounding
+|					;implicity has extend precision
+|					;in upper word. 
+	bras	sintexc			
+|
+|	SINTDO
+|
+|	Input:	a0 points to an IEEE extended format operand
+| 	Output:	fp0 has the result 
+|
+| Exeptions:
+|
+| If the subroutine results in an inexact operation, the inx2 and
+| ainx bits in the USER_FPSR are set.
+|
+|
+	.global	sintdo
+sintdo:
+	bfextu	FPCR_MODE(%a6){#2:#2},%d1	|use user's mode for rounding
+|					;implicitly has ext precision
+|					;in upper word. 
+	movel	%d1,L_SCR1(%a6)		|save mode bits
+|
+| Real work of sint is in sintexc
+|
+sintexc:
+	bclrb	#sign_bit,LOCAL_EX(%a0)	|convert to internal extended
+|					;format
+	sne	LOCAL_SGN(%a0)		
+	cmpw	#0x403e,LOCAL_EX(%a0)	|check if (unbiased) exp > 63
+	bgts	out_rnge			|branch if exp < 63
+	cmpw	#0x3ffd,LOCAL_EX(%a0)	|check if (unbiased) exp < 0
+	bgt	in_rnge			|if 63 >= exp > 0, do calc
+|
+| Input is less than zero.  Restore sign, and check for directed
+| rounding modes.  L_SCR1 contains the rmode in the lower byte.
+|
+un_rnge:
+	btstb	#1,L_SCR1+3(%a6)		|check for rn and rz
+	beqs	un_rnrz
+	tstb	LOCAL_SGN(%a0)		|check for sign
+	bnes	un_rmrp_neg
+|
+| Sign is +.  If rp, load +1.0, if rm, load +0.0
+|
+	cmpib	#3,L_SCR1+3(%a6)		|check for rp
+	beqs	un_ldpone		|if rp, load +1.0
+	bsr	ld_pzero		|if rm, load +0.0
+	bra	t_inx2
+un_ldpone:
+	bsr	ld_pone
+	bra	t_inx2
+|
+| Sign is -.  If rm, load -1.0, if rp, load -0.0
+|
+un_rmrp_neg:
+	cmpib	#2,L_SCR1+3(%a6)		|check for rm
+	beqs	un_ldmone		|if rm, load -1.0
+	bsr	ld_mzero		|if rp, load -0.0
+	bra	t_inx2
+un_ldmone:
+	bsr	ld_mone
+	bra	t_inx2
+|
+| Rmode is rn or rz; return signed zero
+|
+un_rnrz:
+	tstb	LOCAL_SGN(%a0)		|check for sign
+	bnes	un_rnrz_neg
+	bsr	ld_pzero
+	bra	t_inx2
+un_rnrz_neg:
+	bsr	ld_mzero
+	bra	t_inx2
+	
+|
+| Input is greater than 2^63.  All bits are significant.  Return
+| the input.
+|
+out_rnge:
+	bfclr	LOCAL_SGN(%a0){#0:#8}	|change back to IEEE ext format
+	beqs	intps
+	bsetb	#sign_bit,LOCAL_EX(%a0)
+intps:
+	fmovel	%fpcr,-(%sp)
+	fmovel	#0,%fpcr
+	fmovex LOCAL_EX(%a0),%fp0	|if exp > 63
+|					;then return X to the user
+|					;there are no fraction bits
+	fmovel	(%sp)+,%fpcr
+	rts
+
+in_rnge:
+| 					;shift off fraction bits
+	clrl	%d0			|clear d0 - initial g,r,s for
+|					;dnrm_lp
+	movel	#0x403e,%d1		|set threshold for dnrm_lp
+|					;assumes a0 points to operand
+	bsr	dnrm_lp
+|					;returns unnormalized number
+|					;pointed by a0
+|					;output d0 supplies g,r,s
+|					;used by round
+	movel	L_SCR1(%a6),%d1		|use selected rounding mode
+|
+|
+	bsr	round			|round the unnorm based on users
+|					;input	a0 ptr to ext X
+|					;	d0 g,r,s bits
+|					;	d1 PREC/MODE info
+|					;output a0 ptr to rounded result
+|					;inexact flag set in USER_FPSR
+|					;if initial grs set
+|
+| normalize the rounded result and store value in fp0
+|
+	bsr	nrm_set			|normalize the unnorm
+|					;Input: a0 points to operand to
+|					;be normalized
+|					;Output: a0 points to normalized
+|					;result
+	bfclr	LOCAL_SGN(%a0){#0:#8}
+	beqs	nrmrndp
+	bsetb	#sign_bit,LOCAL_EX(%a0)	|return to IEEE extended format
+nrmrndp:
+	fmovel	%fpcr,-(%sp)
+	fmovel	#0,%fpcr
+	fmovex LOCAL_EX(%a0),%fp0	|move result to fp0
+	fmovel	(%sp)+,%fpcr
+	rts
+
+	|end