xref: /original-bsd/old/libm/libm/VAX/sincos.s (revision 60c3b96a)
1#
2# Copyright (c) 1985 Regents of the University of California.
3#
4# Use and reproduction of this software are granted  in  accordance  with
5# the terms and conditions specified in  the  Berkeley  Software  License
6# Agreement (in particular, this entails acknowledgement of the programs'
7# source, and inclusion of this notice) with the additional understanding
8# that  all  recipients  should regard themselves as participants  in  an
9# ongoing  research  project and hence should  feel  obligated  to report
10# their  experiences (good or bad) with these elementary function  codes,
11# using "sendbug 4bsd-bugs@BERKELEY", to the authors.
12#
13
14# @(#)sincos.s	1.1 (Berkeley) 08/21/85
15
16#  This is the implementation of Peter Tang's double precision
17#  sine and cosine for the VAX using Bob Corbett's argument reduction.
18#
19#  Notes:
20#       under 1,024,000 random arguments testing on [0,2*pi]
21#       sin() observed maximum error = 0.814 ulps
22#       cos() observed maximum error = 0.792 ulps
23#
24# double sin(arg)
25# double arg;
26# method: true range reduction to [-pi/4,pi/4], P. Tang  &  B. Corbett
27# S. McDonald, April 4,  1985
28#
29	.globl	_sin
30	.text
31	.align	1
32
33_sin:	.word	0xffc		# save r2-r11
34	movq	4(ap),r0
35	bicw3	$0x807f,r0,r2
36	beql	1f		# if x is zero or reserved operand then return x
37#
38# Save the PSL's IV & FU bits on the stack.
39#
40	movpsl	r2
41	bicw3	$0xff9f,r2,-(sp)
42#
43# Clear the IV & FU bits.
44#
45	bicpsw	$0x0060
46#
47#  Entered by  sine    ; save  0  in  r4 .
48#
49	jsb	libm$argred
50	movl	$0,r4
51	jsb	libm$sincos
52	bispsw	(sp)+
531:	ret
54
55#
56# double cos(arg)
57# double arg;
58# method: true range reduction to [-pi/4,pi/4], P. Tang  &  B. Corbett
59# S. McDonald, April 4,  1985
60#
61	.globl	_cos
62	.text
63	.align	1
64
65_cos:	.word	0xffc		# save r2-r11
66	movq	4(ap),r0
67	bicw3	$0x7f,r0,r2
68	cmpw	$0x8000,r2
69	beql	1f		# if x is reserved operand then return x
70#
71# Save the PSL's IV & FU bits on the stack.
72#
73	movpsl	r2
74	bicw3	$0xff9f,r2,-(sp)
75#
76# Clear the IV & FU bits.
77#
78	bicpsw	$0x0060
79#
80#  Entered by  cosine  ; save  1  in  r4 .
81#
82	jsb	libm$argred
83	movl	$1,r4
84	jsb	libm$sincos
85	bispsw	(sp)+
861:	ret
87