[unix-history] / usr / src / libnm / log.s

# double log(arg) ; natural logarithm
# double log10(arg); base 10 log
# double arg
# if(arg<=0){ errno=EDOM; return(-1.7e+38); }
# nat. log computed from Hart&Cheney LOGE 2706 D=22.1
# J F Jarvis August 3, 1978
.set	EDOM,33
.globl	_log
.globl	_log10
.globl	_errno
.text
.align	1
_log10:
	.word	0x0
	movd	4(ap),-(sp)
	calls	$2,_log
	muld2	log10e,r0
	ret
.align	1
_log:
	.word	0x07c0
	movd	4(ap),r0
	jgtr	range
	movl	$EDOM,_errno
	movd	$0d-1.7e+38,r0	# machine dept max neg
	ret
range:
	extzv	$7,$8,r0,r10	# r10 = exp(arg)+128
	insv	$128,$7,$8,r0	# r0,r1: 0.5<=frac(arg)<1.0
	cmpd	r0,sqrt2d2
	jgeq	comp
	insv	$129,$7,$8,r0	# frac *= 2
	decl	r10				# exp -= 1
comp:
	subl2	$128,r10	# signed exp for scaled arg
	subd3	$0d1.0e+0,r0,r6	# Hart&cheney LOGE 2706
	addd2	$0d1.0e+0,r0
	divd2	r0,r6	# r6,r7= (frac-1)/(frac+1)
	muld3	r6,r6,r8
	polyd	r8,$3,pcoef
	muld2	r0,r6
	polyd	r8,$4,qcoef
	divd3	r0,r6,r0
	cvtld	r10,r2
	muld2	log2,r2	# r2,r3= loge(2**exp)
	addd2	r2,r0
	ret
.data
.align	3
pcoef:
	.double	0d-0.24550691103445385056e+2
	.double	0d0.23616053565907671809e+3
	.double	0d-0.54904361859132995001e+3
	.double	0d0.35621151669903912407e+3
qcoef:
	.double	0d0.10e+1
	.double	0d-0.35526251110400238735e+2
	.double	0d0.19375591463035879517e+3
	.double	0d-0.33389039541217149928e+3
	.double 0d0.17810575834951956204e+3
log10e:
	.double	0d0.43429448190325182765e+0
sqrt2d2:
	.double	0d0.70710678118654752440e+0
log2:
	.double	0d0.69314718055994530941e+0
Commit	Line	Data
3f081cf4 TL	1	# double log(arg) ; natural logarithm
	2	# double log10(arg); base 10 log
	3	# double arg
	4	# if(arg<=0){ errno=EDOM; return(-1.7e+38); }
	5	# nat. log computed from Hart&Cheney LOGE 2706 D=22.1
	6	# J F Jarvis August 3, 1978
	7	.set EDOM,33
	8	.globl _log
	9	.globl _log10
	10	.globl _errno
	11	.text
	12	.align 1
	13	_log10:
	14	.word 0x0
	15	movd 4(ap),-(sp)
	16	calls $2,_log
	17	muld2 log10e,r0
	18	ret
	19	.align 1
	20	_log:
	21	.word 0x07c0
	22	movd 4(ap),r0
	23	jgtr range
	24	movl $EDOM,_errno
	25	movd $0d-1.7e+38,r0 # machine dept max neg
	26	ret
	27	range:
	28	extzv $7,$8,r0,r10 # r10 = exp(arg)+128
	29	insv $128,$7,$8,r0 # r0,r1: 0.5<=frac(arg)<1.0
	30	cmpd r0,sqrt2d2
	31	jgeq comp
	32	insv $129,$7,$8,r0 # frac *= 2
	33	decl r10 # exp -= 1
	34	comp:
	35	subl2 $128,r10 # signed exp for scaled arg
	36	subd3 $0d1.0e+0,r0,r6 # Hart&cheney LOGE 2706
	37	addd2 $0d1.0e+0,r0
	38	divd2 r0,r6 # r6,r7= (frac-1)/(frac+1)
	39	muld3 r6,r6,r8
	40	polyd r8,$3,pcoef
	41	muld2 r0,r6
	42	polyd r8,$4,qcoef
	43	divd3 r0,r6,r0
	44	cvtld r10,r2
	45	muld2 log2,r2 # r2,r3= loge(2**exp)
	46	addd2 r2,r0
	47	ret
	48	.data
	49	.align 3
	50	pcoef:
	51	.double 0d-0.24550691103445385056e+2
	52	.double 0d0.23616053565907671809e+3
	53	.double 0d-0.54904361859132995001e+3
	54	.double 0d0.35621151669903912407e+3
	55	qcoef:
	56	.double 0d0.10e+1
	57	.double 0d-0.35526251110400238735e+2
	58	.double 0d0.19375591463035879517e+3
	59	.double 0d-0.33389039541217149928e+3
	60	.double 0d0.17810575834951956204e+3
	61	log10e:
	62	.double 0d0.43429448190325182765e+0
	63	sqrt2d2:
	64	.double 0d0.70710678118654752440e+0
65	log2:
66	.double 0d0.69314718055994530941e+0