/*      $OpenBSD: setjmp.h,v 1.2 2023/04/11 00:45:07 jsg Exp $  */
/*      $NetBSD: setjmp.h,v 1.2 2001/08/25 14:45:59 bjh21 Exp $ */

/*
 * machine/setjmp.h: machine dependent setjmp-related information.
 */

#define _JBLEN  64              /* size, in longs, of a jmp_buf */

/*
 * NOTE: The internal structure of a jmp_buf is *PRIVATE*
 *       This information is provided as there is software
 *       that fiddles with this with obtain the stack pointer
 *       (yes really ! and it's commercial !).
 *
 * Description of the setjmp buffer
 *
 * word  0      magic number    (dependant on creator)
 *       1 -  3 f4              fp register 4
 *       4 -  6 f5              fp register 5
 *       7 -  9 f6              fp register 6
 *      10 - 12 f7              fp register 7
 *      13      fpsr            fp status register
 *      14      r4              register 4
 *      15      r5              register 5
 *      16      r6              register 6
 *      17      r7              register 7
 *      18      r8              register 8
 *      19      r9              register 9
 *      20      r10             register 10 (sl)
 *      21      r11             register 11 (fp)
 *      22      r12             register 12 (ip)
 *      23      r13             register 13 (sp)
 *      24      r14             register 14 (lr)
 *      25      signal mask     (dependant on magic)
 *      26      (con't)
 *      27      (con't)
 *      28      (con't)
 *
 * The magic number identifies the jmp_buf and
 * how the buffer was created as well as providing
 * a sanity check.
 *
 * A side note I should mention - please do not tamper
 * with the floating point fields. While they are
 * always saved and restored at the moment this cannot
 * be guaranteed especially if the compiler happens
 * to be generating soft-float code so no fp
 * registers will be used.
 *
 * Whilst this can be seen an encouraging people to
 * use the setjmp buffer in this way I think that it
 * is for the best then if changes occur compiles will
 * break rather than just having new builds falling over
 * mysteriously.
 */

#define _JB_MAGIC__SETJMP       0x4278f500
#define _JB_MAGIC_SETJMP        0x4278f501

/* Valid for all jmp_buf's */

#define _JB_MAGIC                0
#define _JB_REG_F4               1
#define _JB_REG_F5               4
#define _JB_REG_F6               7
#define _JB_REG_F7              10
#define _JB_REG_FPSR            13
#define _JB_REG_R4              14
#define _JB_REG_R5              15
#define _JB_REG_R6              16
#define _JB_REG_R7              17
#define _JB_REG_R8              18
#define _JB_REG_R9              19
#define _JB_REG_R10             20
#define _JB_REG_R11             21
#define _JB_REG_R12             22
#define _JB_REG_R13             23
#define _JB_REG_R14             24

/* Only valid with the _JB_MAGIC_SETJMP magic */

#define _JB_SIGMASK             25