WebSVN - shark - Blame - Rev 307 - /shark/trunk/oslib/kl/timeint.s

Rev	Author	Line No.	Line
2	pj	1	/* Project: OSLib
		2	* Description: The OS Construction Kit
		3	* Date: 1.6.2000
		4	* Idea by: Luca Abeni & Gerardo Lamastra
		5	*
		6	* OSLib is an SO project aimed at developing a common, easy-to-use
		7	* low-level infrastructure for developing OS kernels and Embedded
		8	* Applications; it partially derives from the HARTIK project but it
		9	* currently is independently developed.
		10	*
		11	* OSLib is distributed under GPL License, and some of its code has
		12	* been derived from the Linux kernel source; also some important
		13	* ideas come from studying the DJGPP go32 extender.
		14	*
		15	* We acknowledge the Linux Community, Free Software Foundation,
		16	* D.J. Delorie and all the other developers who believe in the
		17	* freedom of software and ideas.
		18	*
		19	* For legalese, check out the included GPL license.
		20	*/
		21
		22	/* Safe abort routine & timer asm handler */
		23
		24	.title "Timer.S"
		25
		26	#include <ll/i386/sel.h>
		27	#include <ll/i386/linkage.h>
		28	#include <ll/i386/defs.h>
		29
		30	#include <ll/sys/ll/exc.h>
		31
		32	.data
		33
		34	ASMFILE(TimerHandler)
		35
		36	.extern JmpSel
		37	.extern JmpZone
		38	.globl SYMBOL_NAME(ll_clock)
		39	.globl SYMBOL_NAME(last_handler)
		40
		41	/* Used as JMP entry point to check if a real */
		42	/* context switch is necessary */
		43
		44	SYMBOL_NAME_LABEL(ll_clock) .int 0
		45	SYMBOL_NAME_LABEL(last_handler) .long 0
		46
		47	.extern SYMBOL_NAME(periodic_wake_up)
		48	.extern SYMBOL_NAME(oneshot_wake_up)
		49
		50	.text
299	giacomo	51	.globl SYMBOL_NAME(ll_apic_timer)
		52	/* APIC ll_timer */
		53
		54	SYMBOL_NAME_LABEL(ll_apic_timer)
		55	pushal
		56	pushw %ds
		57	pushw %es
		58	pushw %fs
		59	pushw %gs
305	giacomo	60
		61	/* Send ACK to APIC */
		62	movl $0xFEE000B0,%ebx
		63	movl $0,(%ebx)
		64
299	giacomo	65	movw $(X_FLATDATA_SEL),%ax
		66	movw %ax,%ds
		67	movw %ax,%es
		68
		69	/* Call wake_up(actual_context) */
		70
		71	movl SYMBOL_NAME(ll_clock),%eax
		72	incl %eax
		73	movl %eax,SYMBOL_NAME(ll_clock)
		74
		75	/* The following could be optimized a little... */
		76	xorl %ebx, %ebx
		77	movw %ss, %bx
		78	/* We must switch to a ``safe stack'' */
		79	/*
		80	* OK, this is the idea: in %esp we have the address of the
		81	* stack pointer in the APPLICATION address space...
		82	* We assume that address spaces are implemented through segments...
		83	* What we have to do is to add the segment base to %esp:
		84	* - Load the GDT base in a register
		85	* - Add DS * 8 to that value
		86	* - Read the corresponding GDT entry (the segment descriptor)
		87	* - Compute the base...
		88	* It is (p & 0xFC) \| ((p +1) & 0x0F) << 16) \| *(p + 2)
		89	*/
		90	movl SYMBOL_NAME(GDT_base), %edi
		91	addl %ebx, %edi
		92	xorl %ebx, %ebx
		93	movb 7(%edi), %bh
		94	movb 4(%edi), %bl
		95	shl $16, %ebx
		96	movw 2(%edi), %bx
		97	/* Is it correct? I think so... Test it!!! */
		98	addl %ebx, %esp
		99	/* Save EBX for returning to our stack... */
		100	movw %ds, %cx
		101	movw %ss, %dx
		102	movw %cx, %ss
		103	pushl %ebx
		104	pushl %edx
		105	cld
		106	movl SYMBOL_NAME(timermode), %eax
		107	cmpl $1, %eax
		108	je apic_oneshot
		109	call SYMBOL_NAME(periodic_wake_up)
		110	jmp apic_Timer_OK
		111	apic_oneshot: call SYMBOL_NAME(oneshot_wake_up)
		112	apic_Timer_OK:
		113	/* Restore ESP */
		114	popl %edx
		115	popl %ebx /* We must subtract it from ESP...*/
		116	subl %ebx, %esp
		117	movw %dx, %ss
		118
		119	#ifdef __VIRCSW__
		120
		121	movw SYMBOL_NAME(currCtx), %ax
		122	cmpw %ax,JmpSel
		123	je apic_NoPreempt2
		124	movw %ax,JmpSel
		125	ljmp JmpZone /* DISPATCH! */
		126	#endif
		127	apic_NoPreempt2:
		128
		129	cmpl $0, SYMBOL_NAME(last_handler)
		130	je apic_nohandler
		131	movl SYMBOL_NAME(last_handler), %ebx
		132	call *%ebx
		133	apic_nohandler:
305	giacomo	134
299	giacomo	135	popw %gs
		136	popw %fs
		137	popw %es
		138	popw %ds
		139	popal
		140	iret
		141
2	pj	142	.globl SYMBOL_NAME(ll_timer)
		143	/* This is the timer handler; it reloads for safety the DS register; this */
		144	/* prevents from mess when timer interrupts linear access to memory (not in */
		145	/* ELF address space); then EOI is sent in order to detect timer overrun */
		146	/* The high level kernel procedure wake_up() is called to perform the */
		147	/* preeption at higher level (process descriptos); the resulting context */
		148	/* if different from the old one is used to trigger the task activation. */
		149
		150	SYMBOL_NAME_LABEL(ll_timer)
		151	pushal
		152	pushw %ds
		153	pushw %es
		154	pushw %fs
		155	pushw %gs
305	giacomo	156
		157	/* Send ACK to master PIC */
		158	movb $0x20,%al
		159	movl $0x20,%edx
		160	outb %al,%dx
2	pj	161
		162	movw $(X_FLATDATA_SEL),%ax
		163	movw %ax,%ds
		164	movw %ax,%es
		165
		166	/* Call wake_up(actual_context) */
		167
		168	movl SYMBOL_NAME(ll_clock),%eax
		169	incl %eax
		170	movl %eax,SYMBOL_NAME(ll_clock)
		171
		172	/* The following could be optimized a little... */
		173	xorl %ebx, %ebx
		174	movw %ss, %bx
		175	/* We must switch to a ``safe stack'' */
		176	/*
		177	* OK, this is the idea: in %esp we have the address of the
		178	* stack pointer in the APPLICATION address space...
		179	* We assume that address spaces are implemented through segments...
		180	* What we have to do is to add the segment base to %esp:
		181	* - Load the GDT base in a register
		182	* - Add DS * 8 to that value
		183	* - Read the corresponding GDT entry (the segment descriptor)
		184	* - Compute the base...
		185	* It is (p & 0xFC) \| ((p +1) & 0x0F) << 16) \| *(p + 2)
		186	*/
		187	movl SYMBOL_NAME(GDT_base), %edi
		188	addl %ebx, %edi
		189	xorl %ebx, %ebx
		190	movb 7(%edi), %bh
		191	movb 4(%edi), %bl
		192	shl $16, %ebx
		193	movw 2(%edi), %bx
		194	/* Is it correct? I think so... Test it!!! */
		195	addl %ebx, %esp
		196	/* Save EBX for returning to our stack... */
		197	movw %ds, %cx
		198	movw %ss, %dx
		199	movw %cx, %ss
		200	pushl %ebx
		201	pushl %edx
		202	cld
		203	movl SYMBOL_NAME(timermode), %eax
		204	cmpl $1, %eax
		205	je oneshot
		206	call SYMBOL_NAME(periodic_wake_up)
		207	jmp goon
		208	oneshot: call SYMBOL_NAME(oneshot_wake_up)
227	giacomo	209	jmp Timer_OK
2	pj	210	goon:
		211	/* This is the overrun test */
		212	/* Do it after sending EOI to master PIC */
		213
		214	movb $0x0A,%al
		215	movl $0x020,%edx
		216	outb %al,%dx
		217	inb %dx,%al
		218	testb $1,%al
		219	jz Timer_OK
		220	movl $(CLOCK_OVERRUN),%eax
		221	pushl %eax
		222	call SYMBOL_NAME(ll_abort)
		223
		224	Timer_OK:
		225	/* Restore ESP */
		226	popl %edx
		227	popl %ebx /* We must subtract it from ESP...*/
		228	subl %ebx, %esp
		229	movw %dx, %ss
40	pj	230
2	pj	231	#ifdef __VIRCSW__
		232
		233	movw SYMBOL_NAME(currCtx), %ax
		234	cmpw %ax,JmpSel
		235	je NoPreempt2
		236	movw %ax,JmpSel
		237	ljmp JmpZone /* DISPATCH! */
		238	#endif
		239	NoPreempt2:
		240
		241	cmpl $0, SYMBOL_NAME(last_handler)
		242	je nohandler
		243	movl SYMBOL_NAME(last_handler), %ebx
		244	call *%ebx
		245	nohandler:
305	giacomo	246
2	pj	247	popw %gs
		248	popw %fs
		249	popw %es
		250	popw %ds
		251	popal
		252	iret

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