[unix-history] / src / px / 30atof.s

/ C library -- ascii to floating

/	f = atof(p)
/	char *p;

ldfps = 170100^tst
stfps = 170200^tst

.globl	_atof

.globl	csv, cret

_atof:
	jsr	r5,csv
	stfps	-(sp)
	ldfps	$200
	movf	fr1,-(sp)
	clr	-(sp)
	clrf	fr0
	clr	r2
	mov	4(r5),r3
1:
	movb	(r3)+,r0
	cmp	$' ,r0
	beq	1b
	cmpb	r0,$'-
	bne	2f
	inc	(sp)
1:
	movb	(r3)+,r0
2:
	sub	$'0,r0
	cmp	r0,$9.
	bhi	2f
	jsr	pc,digit
		br 1b
	inc	r2
	br	1b
2:
	cmpb	r0,$'.-'0
	bne	2f
1:
	movb	(r3)+,r0
	sub	$'0,r0
	cmp	r0,$9.
	bhi	2f
	jsr	pc,digit
		dec r2
	br	1b
2:
	cmpb	r0,$'E-'0
	beq	3f
	cmpb	r0,$'e-'0
	bne	1f
3:
	clr	r4
	clr	r1
	cmpb	(r3),$'-
	bne	3f
	inc	r4
	inc	r3
3:
	movb	(r3)+,r0
	sub	$'0,r0
	cmp	r0,$9.
	bhi	3f
	mul	$10.,r1
	add	r0,r1
	br	3b
3:
	tst	r4
	bne	3f
	neg	r1
3:
	sub	r1,r2
1:
	movf	$one,fr1
	mov	r2,-(sp)
	beq	2f
	bgt	1f
	neg	r2
1:
	cmp	r2,$38.
	blos	1f
	clrf	fr0
	tst	(sp)+
	bmi	out
	movf	$huge,fr0
	br	out
1:
	mulf	$ten,fr1
	sob	r2,1b
2:
	tst	(sp)+
	bge	1f
	divf	fr1,fr0
	br	2f
1:
	mulf	fr1,fr0
	cfcc
	bvc	2f
	movf	$huge,fr0
2:
out:
	tst	(sp)+
	beq	1f
	negf	fr0
1:
	movf	(sp)+,fr1
	ldfps	(sp)+
	jmp	cret
/
/
digit:
	cmpf	$big,fr0
	cfcc
	blt	1f
	mulf	$ten,fr0
	movif	r0,fr1
	addf	fr1,fr0
	rts	pc
1:
	add	$2,(sp)
	rts	pc
/
/
one	= 40200
ten	= 41040
big	= 56200
huge	= 77777
Commit	Line	Data
ed4c4f10 BJ	1	/ C library -- ascii to floating
	2
	3	/ f = atof(p)
	4	/ char *p;
	5
	6	ldfps = 170100^tst
	7	stfps = 170200^tst
	8
	9	.globl _atof
	10
	11	.globl csv, cret
	12
	13	_atof:
	14	jsr r5,csv
	15	stfps -(sp)
	16	ldfps $200
	17	movf fr1,-(sp)
	18	clr -(sp)
	19	clrf fr0
	20	clr r2
	21	mov 4(r5),r3
	22	1:
	23	movb (r3)+,r0
	24	cmp $' ,r0
	25	beq 1b
	26	cmpb r0,$'-
	27	bne 2f
	28	inc (sp)
	29	1:
	30	movb (r3)+,r0
	31	2:
	32	sub $'0,r0
	33	cmp r0,$9.
	34	bhi 2f
	35	jsr pc,digit
	36	br 1b
	37	inc r2
	38	br 1b
	39	2:
	40	cmpb r0,$'.-'0
	41	bne 2f
	42	1:
	43	movb (r3)+,r0
	44	sub $'0,r0
	45	cmp r0,$9.
	46	bhi 2f
	47	jsr pc,digit
	48	dec r2
	49	br 1b
	50	2:
	51	cmpb r0,$'E-'0
	52	beq 3f
	53	cmpb r0,$'e-'0
	54	bne 1f
	55	3:
	56	clr r4
	57	clr r1
	58	cmpb (r3),$'-
	59	bne 3f
	60	inc r4
	61	inc r3
	62	3:
	63	movb (r3)+,r0
	64	sub $'0,r0
65	cmp r0,$9.
66	bhi 3f
67	mul $10.,r1
68	add r0,r1
69	br 3b
70	3:
71	tst r4
72	bne 3f
73	neg r1
74	3:
75	sub r1,r2
76	1:
77	movf $one,fr1
78	mov r2,-(sp)
79	beq 2f
80	bgt 1f
81	neg r2
82	1:
83	cmp r2,$38.
84	blos 1f
85	clrf fr0
86	tst (sp)+
87	bmi out
88	movf $huge,fr0
89	br out
90	1:
91	mulf $ten,fr1
92	sob r2,1b
93	2:
94	tst (sp)+
95	bge 1f
96	divf fr1,fr0
97	br 2f
98	1:
99	mulf fr1,fr0
100	cfcc
101	bvc 2f
102	movf $huge,fr0
103	2:
104	out:
105	tst (sp)+
106	beq 1f
107	negf fr0
108	1:
109	movf (sp)+,fr1
110	ldfps (sp)+
111	jmp cret
112	/
113	/
114	digit:
115	cmpf $big,fr0
116	cfcc
117	blt 1f
118	mulf $ten,fr0
119	movif r0,fr1
120	addf fr1,fr0
121	rts pc
122	1:
123	add $2,(sp)
124	rts pc
125	/
126	/
127	one = 40200
128	ten = 41040
129	big = 56200
130	huge = 77777