kern
view src/proc-asm.S @ 80:4db99a52863e
fixed the "endianess" of the text messages in the ATA identify info block. this
is the first time I've seen wrong byteorder in ascii text, the ATA committee
should be commended.
| author | John Tsiombikas <nuclear@member.fsf.org> |
|---|---|
| date | Tue, 06 Dec 2011 13:35:39 +0200 |
| parents | 437360696883 |
| children |
line source
1 .text
2 /* switch_stack(uint32_t new_stack, uint32_t *old_stack_ptr)
3 * switches to the new stack and returns the old stack pointer, which is
4 * also copied to the address passed as the second argument.
5 */
6 .globl switch_stack
7 switch_stack:
8 movl %esp, %eax /* old stack in eax */
9 movl 8(%esp), %edx
10 cmpl $0, %edx /* if old_stack_ptr is null, skip ahead */
11 jz oldp_is_null
12 movl %eax, (%edx) /* otherwise *old_stack_ptr = eax */
13 oldp_is_null:
14 movl 4(%esp), %esp /* set the new stack */
15 ret
17 /* get_instr_stack_ptr(uint32_t *eip, uint32_t *esp)
18 * returns the current instruction and stack pointers at the same
19 * point in execution, so that a newly-forked process with these
20 * values will just return from this function and continue on.
21 */
22 .globl get_instr_stack_ptr
23 get_instr_stack_ptr:
24 call get_instr_ptr
25 movl %eax, 4(%esp)
26 movl %esp, 8(%esp)
27 ret
29 /* get_instr_ptr(void)
30 * returns the address of the next instruction after the call to this function
31 */
32 .globl get_instr_ptr
33 get_instr_ptr:
34 movl (%esp), %eax
35 ret
37 /* get_caller_instr_ptr(void)
38 * returns the address of the next instruction after the call to the function that
39 * called this function.
40 * NOTE: will only work properly when called from a function that uses ebp to point
41 * to its stack frame, which means all of the C functions but pretty much none of
42 * our assembly functions.
43 */
44 .globl get_caller_instr_ptr
45 get_caller_instr_ptr:
46 movl 4(%ebp), %eax
47 ret
49 /* this is where we end up when we first context_switch to a newly forked
50 * process. The interrupt frame is already there, so we just call intr_ret
51 * to return to user space
52 */
53 .globl just_forked
54 just_forked:
55 call intr_ret