kern
view src/intr-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 | 4eaecb14fe31 |
| children |
line source
1 #define ASM
2 #include "segm.h"
4 .data
5 .align 4
6 .short 0
7 /* memory reserved for set_idt */
8 lim:.short 0
9 addr:.long 0
11 .text
12 /* set_idt(uint32_t addr, uint16_t limit)
13 * loads the IDTR with the new address and limit for the IDT */
14 .globl set_idt
15 set_idt:
16 movl 4(%esp), %eax
17 movl %eax, (addr)
18 movw 8(%esp), %ax
19 movw %ax, (lim)
20 lidt (lim)
21 ret
23 /* get_intr_state()
24 * returns 1 if interrutps are enabled, 0 if disabled */
25 .globl get_intr_state
26 get_intr_state:
27 pushf
28 popl %eax
29 shr $9, %eax /* bit 9 of eflags is IF */
30 andl $1, %eax
31 ret
33 /* set_intr_state(int state)
34 * enables interrupts if the argument is non-zero, disables them otherwise */
35 .globl set_intr_state
36 set_intr_state:
37 cmpl $0, 4(%esp)
38 jz 0f
39 sti
40 ret
41 0: cli
42 ret
45 /* interrupt entry with error code macro
46 * this macro generates an interrupt entry point for the
47 * exceptions which include error codes in the stack frame
48 */
49 .macro ientry_err n name
50 .globl intr_entry_\name
51 intr_entry_\name:
52 pushl $\n
53 jmp intr_entry_common
54 .endm
56 /* interrupt entry without error code macro
57 * this macro generates an interrupt entry point for the interrupts
58 * and exceptions which do not include error codes in the stack frame
59 * it pushes a dummy error code (0), to make the stack frame identical
60 */
61 .macro ientry_noerr n name
62 .globl intr_entry_\name
63 intr_entry_\name:
64 pushl $0
65 pushl $\n
66 jmp intr_entry_common
67 .endm
69 /* common code used by all entry points. calls dispatch_intr()
70 * defined in intr.c
71 */
72 .extern dispatch_intr
73 intr_entry_common:
74 /* save the current data segment selectors */
75 pushl %gs
76 pushl %fs
77 pushl %es
78 pushl %ds
79 /* save general purpose registers */
80 pusha
81 /* if we entered from userspace ss and cs is set correctly, but
82 * we must make sure all the other selectors are set to the
83 * kernel data segment */
84 mov %ss, %eax
85 mov %eax, %ds
86 mov %eax, %es
87 mov %eax, %fs
88 mov %eax, %gs
89 call dispatch_intr
90 intr_ret_local:
91 /* restore general purpose registers */
92 popa
93 /* restore data segment selectors */
94 popl %ds
95 popl %es
96 popl %fs
97 popl %gs
98 /* remove error code and intr num from stack */
99 add $8, %esp
100 iret
102 /* intr_ret is called by context_switch to return from the kernel
103 * to userspace. The argument is a properly formed intr_frame
104 * structure with the saved context of the new task.
105 *
106 * First thing to do is remove the return address pointing back
107 * to context_switch, which then leaves us with a proper interrupt
108 * stack frame, so we can jump right in the middle of the regular
109 * interrupt return code above.
110 */
111 .globl intr_ret
112 intr_ret:
113 add $4, %esp
114 jmp intr_ret_local
116 /* by including interrupts.h with ASM defined, the macros above
117 * are expanded to generate all required interrupt entry points
118 */
119 #include <interrupts.h>