xref: /netbsd-src/sys/arch/arm/include/setjmp.h (revision 5a0167f5d262fc3f9741dee3f530c590a8e9fd26)
1 /*	$NetBSD: setjmp.h,v 1.6 2024/05/06 07:29:30 skrll Exp $	*/
2 
3 /*
4  * machine/setjmp.h: machine dependent setjmp-related information.
5  */
6 
7 #define	_JBLEN	64		/* size, in longs, of a jmp_buf */
8 
9 /*
10  * NOTE: The internal structure of a jmp_buf is *PRIVATE*
11  *       This information is provided as there is software
12  *       that fiddles with this with obtain the stack pointer
13  *	 (yes really ! and it's commercial !).
14  *
15  * Description of the setjmp buffer
16  *
17  * Word		Field		Comment
18  * 	0	magic number	(dependent on creator)
19  *	13	fpscr		vfp status control register
20  *	14	r4		register 4
21  *	15	r5		register 5
22  *	16	r6		register 6
23  *	17	r7		register 7
24  *	18	r8		register 8
25  *	19	r9		register 9
26  *	20	r10		register 10 (sl)
27  *	21	r11		register 11 (fp)
28  *	22	r12		register 12 (ip)
29  *	23	r13		register 13 (sp)
30  *	24	r14		register 14 (lr)
31  *	25	signal mask	(dependent on magic)
32  *	26	(con't)
33  *	27	(con't)
34  *	28	(con't)
35  *	32-33	d8		(vfp register d8)
36  *	34-35	d9		(vfp register d9)
37  *	36-37	d10		(vfp register d10)
38  *	38-39	d11		(vfp register d11)
39  *	40-41	d12		(vfp register d12)
40  *	42-43	d13		(vfp register d13)
41  *	44-45	d14		(vfp register d14)
42  *	46-47	d15		(vfp register d15)
43  *
44  * The magic number number identifies the jmp_buf and
45  * how the buffer was created as well as providing
46  * a sanity check
47  *
48  * A side note I should mention - Please do not tamper
49  * with the floating point fields. While they are
50  * always saved and restored at the moment this cannot
51  * be guaranteed especially if the compiler happens
52  * to be generating soft-float code so no fp
53  * registers will be used.
54  *
55  * Whilst this can be seen as encouraging people to
56  * use the setjmp buffer in this way I think that it
57  * is for the best then, if changes occur, compiles will
58  * break rather than just having new builds falling over
59  * mysteriously.
60  */
61 
62 #define _JB_MAGIC__SETJMP	0x4278f500
63 #define _JB_MAGIC_SETJMP	0x4278f501
64 #define _JB_MAGIC__SETJMP_VFP	0x4278f502
65 #define _JB_MAGIC_SETJMP_VFP	0x4278f503
66 
67 /* Valid for all jmp_buf's */
68 
69 #define _JB_MAGIC		 0
70 #define _JB_REG_FPSCR		13
71 #define _JB_REG_R4		14
72 #define _JB_REG_R5		15
73 #define _JB_REG_R6		16
74 #define _JB_REG_R7		17
75 #define _JB_REG_R8		18
76 #define _JB_REG_R9		19
77 #define _JB_REG_R10		20
78 #define _JB_REG_R11		21
79 #define _JB_REG_R12		22
80 #define _JB_REG_R13		23
81 #define _JB_REG_R14		24
82 
83 /* Only valid with the _JB_MAGIC_SETJMP magic */
84 
85 #define _JB_SIGMASK		25
86 
87 #define	_JB_REG_D8		32
88 #define	_JB_REG_D9		34
89 #define	_JB_REG_D10		36
90 #define	_JB_REG_D11		38
91 #define	_JB_REG_D12		40
92 #define	_JB_REG_D13		42
93 #define	_JB_REG_D14		44
94 #define	_JB_REG_D15		46
95