xref: /linux/arch/x86/math-emu/round_Xsig.S (revision ef69f8d2ff09518657c3ecaf2db8408c16549829) 
1/* SPDX-License-Identifier: GPL-2.0 */
2/*---------------------------------------------------------------------------+
3 |  round_Xsig.S                                                             |
4 |                                                                           |
5 | Copyright (C) 1992,1993,1994,1995                                         |
6 |                       W. Metzenthen, 22 Parker St, Ormond, Vic 3163,      |
7 |                       Australia.  E-mail billm@jacobi.maths.monash.edu.au |
8 |                                                                           |
9 | Normalize and round a 12 byte quantity.                                   |
10 | Call from C as:                                                           |
11 |   int round_Xsig(Xsig *n)                                                 |
12 |                                                                           |
13 | Normalize a 12 byte quantity.                                             |
14 | Call from C as:                                                           |
15 |   int norm_Xsig(Xsig *n)                                                  |
16 |                                                                           |
17 | Each function returns the size of the shift (nr of bits).                 |
18 |                                                                           |
19 +---------------------------------------------------------------------------*/
20	.file	"round_Xsig.S"
21
22#include "fpu_emu.h"
23
24
25.text
26ENTRY(round_Xsig)
27	pushl	%ebp
28	movl	%esp,%ebp
29	pushl	%ebx		/* Reserve some space */
30	pushl	%ebx
31	pushl	%esi
32
33	movl	PARAM1,%esi
34
35	movl	8(%esi),%edx
36	movl	4(%esi),%ebx
37	movl	(%esi),%eax
38
39	movl	$0,-4(%ebp)
40
41	orl	%edx,%edx	/* ms bits */
42	js	L_round		/* Already normalized */
43	jnz	L_shift_1	/* Shift left 1 - 31 bits */
44
45	movl	%ebx,%edx
46	movl	%eax,%ebx
47	xorl	%eax,%eax
48	movl	$-32,-4(%ebp)
49
50/* We need to shift left by 1 - 31 bits */
51L_shift_1:
52	bsrl	%edx,%ecx	/* get the required shift in %ecx */
53	subl	$31,%ecx
54	negl	%ecx
55	subl	%ecx,-4(%ebp)
56	shld	%cl,%ebx,%edx
57	shld	%cl,%eax,%ebx
58	shl	%cl,%eax
59
60L_round:
61	testl	$0x80000000,%eax
62	jz	L_exit
63
64	addl	$1,%ebx
65	adcl	$0,%edx
66	jnz	L_exit
67
68	movl	$0x80000000,%edx
69	incl	-4(%ebp)
70
71L_exit:
72	movl	%edx,8(%esi)
73	movl	%ebx,4(%esi)
74	movl	%eax,(%esi)
75
76	movl	-4(%ebp),%eax
77
78	popl	%esi
79	popl	%ebx
80	leave
81	ret
82ENDPROC(round_Xsig)
83
84
85
86ENTRY(norm_Xsig)
87	pushl	%ebp
88	movl	%esp,%ebp
89	pushl	%ebx		/* Reserve some space */
90	pushl	%ebx
91	pushl	%esi
92
93	movl	PARAM1,%esi
94
95	movl	8(%esi),%edx
96	movl	4(%esi),%ebx
97	movl	(%esi),%eax
98
99	movl	$0,-4(%ebp)
100
101	orl	%edx,%edx	/* ms bits */
102	js	L_n_exit		/* Already normalized */
103	jnz	L_n_shift_1	/* Shift left 1 - 31 bits */
104
105	movl	%ebx,%edx
106	movl	%eax,%ebx
107	xorl	%eax,%eax
108	movl	$-32,-4(%ebp)
109
110	orl	%edx,%edx	/* ms bits */
111	js	L_n_exit	/* Normalized now */
112	jnz	L_n_shift_1	/* Shift left 1 - 31 bits */
113
114	movl	%ebx,%edx
115	movl	%eax,%ebx
116	xorl	%eax,%eax
117	addl	$-32,-4(%ebp)
118	jmp	L_n_exit	/* Might not be normalized,
119	                           but shift no more. */
120
121/* We need to shift left by 1 - 31 bits */
122L_n_shift_1:
123	bsrl	%edx,%ecx	/* get the required shift in %ecx */
124	subl	$31,%ecx
125	negl	%ecx
126	subl	%ecx,-4(%ebp)
127	shld	%cl,%ebx,%edx
128	shld	%cl,%eax,%ebx
129	shl	%cl,%eax
130
131L_n_exit:
132	movl	%edx,8(%esi)
133	movl	%ebx,4(%esi)
134	movl	%eax,(%esi)
135
136	movl	-4(%ebp),%eax
137
138	popl	%esi
139	popl	%ebx
140	leave
141	ret
142ENDPROC(norm_Xsig)
143