1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
|
/*
* coswitch for Sun-4 Sparc.
*
* Compile this with 'gcc -c rswitch.c'. Do not use gcc -O.
*/
#include <sys/asm_linkage.h>
#include <sys/trap.h>
int coswitch(old_cs, new_cs, first)
int *old_cs, *new_cs;
int first;
{
asm("ta 0x03"); /* ST_FLUSH_WINDOWS in trap.h */
asm("ld [%fp+0x44], %o0"); /* load old_cs into %o0 */
asm("st %sp,[%o0]"); /* Save user stack pointer */
asm("st %fp,[%o0+0x4]"); /* Save frame pointer */
asm("st %i7,[%o0+0x8]"); /* Save return address */
if (first == 0) { /* this is the first activation */
asm("ld [%fp+0x48], %o0"); /* load new_cs into %o0 */
asm("ld [%o0], %o1"); /* load %o1 from cstate[0] */
/* Decrement new stack pointer value before loading it into sp. */
/* The top 64 bytes of the stack are reserved for the kernel, to */
/* save the 8 local and 8 in registers into, on context switches, */
/* interrupts, traps, etc. */
asm("save %o1,-96, %sp"); /* load %sp from %o1 */
new_context(0,0);
syserr("new_context() returned in coswitch");
} else {
asm("ld [%fp+0x48], %o0"); /* load new_cs into %o0 */
asm("ld [%o0+0x4],%fp"); /* Load frame pointer */
asm("ld [%o0+0x8],%i7"); /* Load return address */
asm("ld [%o0],%sp"); /* Load user stack pointer */
}
}
|
