1|
2|	sint.sa 3.1 12/10/90
3|
4|	The entry point sINT computes the rounded integer
5|	equivalent of the input argument, sINTRZ computes
6|	the integer rounded to zero of the input argument.
7|
8|	Entry points sint and sintrz are called from do_func
9|	to emulate the fint and fintrz unimplemented instructions,
10|	respectively.  Entry point sintdo is used by bindec.
11|
12|	Input: (Entry points sint and sintrz) Double-extended
13|		number X in the ETEMP space in the floating-point
14|		save stack.
15|	       (Entry point sintdo) Double-extended number X in
16|		location pointed to by the address register a0.
17|	       (Entry point sintd) Double-extended denormalized
18|		number X in the ETEMP space in the floating-point
19|		save stack.
20|
21|	Output: The function returns int(X) or intrz(X) in fp0.
22|
23|	Modifies: fp0.
24|
25|	Algorithm: (sint and sintrz)
26|
27|	1. If exp(X) >= 63, return X.
28|	   If exp(X) < 0, return +/- 0 or +/- 1, according to
29|	   the rounding mode.
30|
31|	2. (X is in range) set rsc = 63 - exp(X). Unnormalize the
32|	   result to the exponent $403e.
33|
34|	3. Round the result in the mode given in USER_FPCR. For
35|	   sintrz, force round-to-zero mode.
36|
37|	4. Normalize the rounded result; store in fp0.
38|
39|	For the denormalized cases, force the correct result
40|	for the given sign and rounding mode.
41|
42|		        Sign(X)
43|		RMODE   +    -
44|		-----  --------
45|		 RN    +0   -0
46|		 RZ    +0   -0
47|		 RM    +0   -1
48|		 RP    +1   -0
49|
50|
51|		Copyright (C) Motorola, Inc. 1990
52|			All Rights Reserved
53|
54|       For details on the license for this file, please see the
55|       file, README, in this same directory.
56
57|SINT    idnt    2,1 | Motorola 040 Floating Point Software Package
58
59	|section	8
60
61#include "fpsp.h"
62
63	|xref	dnrm_lp
64	|xref	nrm_set
65	|xref	round
66	|xref	t_inx2
67	|xref	ld_pone
68	|xref	ld_mone
69	|xref	ld_pzero
70	|xref	ld_mzero
71	|xref	snzrinx
72
73|
74|	FINT
75|
76	.global	sint
77sint:
78	bfextu	FPCR_MODE(%a6){#2:#2},%d1	|use user's mode for rounding
79|					;implicitly has extend precision
80|					;in upper word.
81	movel	%d1,L_SCR1(%a6)		|save mode bits
82	bras	sintexc
83
84|
85|	FINT with extended denorm inputs.
86|
87	.global	sintd
88sintd:
89	btstb	#5,FPCR_MODE(%a6)
90	beq	snzrinx		|if round nearest or round zero, +/- 0
91	btstb	#4,FPCR_MODE(%a6)
92	beqs	rnd_mns
93rnd_pls:
94	btstb	#sign_bit,LOCAL_EX(%a0)
95	bnes	sintmz
96	bsr	ld_pone		|if round plus inf and pos, answer is +1
97	bra	t_inx2
98rnd_mns:
99	btstb	#sign_bit,LOCAL_EX(%a0)
100	beqs	sintpz
101	bsr	ld_mone		|if round mns inf and neg, answer is -1
102	bra	t_inx2
103sintpz:
104	bsr	ld_pzero
105	bra	t_inx2
106sintmz:
107	bsr	ld_mzero
108	bra	t_inx2
109
110|
111|	FINTRZ
112|
113	.global	sintrz
114sintrz:
115	movel	#1,L_SCR1(%a6)		|use rz mode for rounding
116|					;implicitly has extend precision
117|					;in upper word.
118	bras	sintexc
119|
120|	SINTDO
121|
122|	Input:	a0 points to an IEEE extended format operand
123|	Output:	fp0 has the result
124|
125| Exceptions:
126|
127| If the subroutine results in an inexact operation, the inx2 and
128| ainx bits in the USER_FPSR are set.
129|
130|
131	.global	sintdo
132sintdo:
133	bfextu	FPCR_MODE(%a6){#2:#2},%d1	|use user's mode for rounding
134|					;implicitly has ext precision
135|					;in upper word.
136	movel	%d1,L_SCR1(%a6)		|save mode bits
137|
138| Real work of sint is in sintexc
139|
140sintexc:
141	bclrb	#sign_bit,LOCAL_EX(%a0)	|convert to internal extended
142|					;format
143	sne	LOCAL_SGN(%a0)
144	cmpw	#0x403e,LOCAL_EX(%a0)	|check if (unbiased) exp > 63
145	bgts	out_rnge			|branch if exp < 63
146	cmpw	#0x3ffd,LOCAL_EX(%a0)	|check if (unbiased) exp < 0
147	bgt	in_rnge			|if 63 >= exp > 0, do calc
148|
149| Input is less than zero.  Restore sign, and check for directed
150| rounding modes.  L_SCR1 contains the rmode in the lower byte.
151|
152un_rnge:
153	btstb	#1,L_SCR1+3(%a6)		|check for rn and rz
154	beqs	un_rnrz
155	tstb	LOCAL_SGN(%a0)		|check for sign
156	bnes	un_rmrp_neg
157|
158| Sign is +.  If rp, load +1.0, if rm, load +0.0
159|
160	cmpib	#3,L_SCR1+3(%a6)		|check for rp
161	beqs	un_ldpone		|if rp, load +1.0
162	bsr	ld_pzero		|if rm, load +0.0
163	bra	t_inx2
164un_ldpone:
165	bsr	ld_pone
166	bra	t_inx2
167|
168| Sign is -.  If rm, load -1.0, if rp, load -0.0
169|
170un_rmrp_neg:
171	cmpib	#2,L_SCR1+3(%a6)		|check for rm
172	beqs	un_ldmone		|if rm, load -1.0
173	bsr	ld_mzero		|if rp, load -0.0
174	bra	t_inx2
175un_ldmone:
176	bsr	ld_mone
177	bra	t_inx2
178|
179| Rmode is rn or rz; return signed zero
180|
181un_rnrz:
182	tstb	LOCAL_SGN(%a0)		|check for sign
183	bnes	un_rnrz_neg
184	bsr	ld_pzero
185	bra	t_inx2
186un_rnrz_neg:
187	bsr	ld_mzero
188	bra	t_inx2
189
190|
191| Input is greater than 2^63.  All bits are significant.  Return
192| the input.
193|
194out_rnge:
195	bfclr	LOCAL_SGN(%a0){#0:#8}	|change back to IEEE ext format
196	beqs	intps
197	bsetb	#sign_bit,LOCAL_EX(%a0)
198intps:
199	fmovel	%fpcr,-(%sp)
200	fmovel	#0,%fpcr
201	fmovex LOCAL_EX(%a0),%fp0	|if exp > 63
202|					;then return X to the user
203|					;there are no fraction bits
204	fmovel	(%sp)+,%fpcr
205	rts
206
207in_rnge:
208|					;shift off fraction bits
209	clrl	%d0			|clear d0 - initial g,r,s for
210|					;dnrm_lp
211	movel	#0x403e,%d1		|set threshold for dnrm_lp
212|					;assumes a0 points to operand
213	bsr	dnrm_lp
214|					;returns unnormalized number
215|					;pointed by a0
216|					;output d0 supplies g,r,s
217|					;used by round
218	movel	L_SCR1(%a6),%d1		|use selected rounding mode
219|
220|
221	bsr	round			|round the unnorm based on users
222|					;input	a0 ptr to ext X
223|					;	d0 g,r,s bits
224|					;	d1 PREC/MODE info
225|					;output a0 ptr to rounded result
226|					;inexact flag set in USER_FPSR
227|					;if initial grs set
228|
229| normalize the rounded result and store value in fp0
230|
231	bsr	nrm_set			|normalize the unnorm
232|					;Input: a0 points to operand to
233|					;be normalized
234|					;Output: a0 points to normalized
235|					;result
236	bfclr	LOCAL_SGN(%a0){#0:#8}
237	beqs	nrmrndp
238	bsetb	#sign_bit,LOCAL_EX(%a0)	|return to IEEE extended format
239nrmrndp:
240	fmovel	%fpcr,-(%sp)
241	fmovel	#0,%fpcr
242	fmovex LOCAL_EX(%a0),%fp0	|move result to fp0
243	fmovel	(%sp)+,%fpcr
244	rts
245
246	|end
247