WebSVN - shark - Blame - Rev 305 - /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	cli
		62
		63	/* Send ACK to APIC */
		64	movl $0xFEE000B0,%ebx
		65	movl $0,(%ebx)
		66
299	giacomo	67	movw $(X_FLATDATA_SEL),%ax
		68	movw %ax,%ds
		69	movw %ax,%es
		70
		71	/* Call wake_up(actual_context) */
		72
		73	movl SYMBOL_NAME(ll_clock),%eax
		74	incl %eax
		75	movl %eax,SYMBOL_NAME(ll_clock)
		76
		77	/* The following could be optimized a little... */
		78	xorl %ebx, %ebx
		79	movw %ss, %bx
		80	/* We must switch to a ``safe stack'' */
		81	/*
		82	* OK, this is the idea: in %esp we have the address of the
		83	* stack pointer in the APPLICATION address space...
		84	* We assume that address spaces are implemented through segments...
		85	* What we have to do is to add the segment base to %esp:
		86	* - Load the GDT base in a register
		87	* - Add DS * 8 to that value
		88	* - Read the corresponding GDT entry (the segment descriptor)
		89	* - Compute the base...
		90	* It is (p & 0xFC) \| ((p +1) & 0x0F) << 16) \| *(p + 2)
		91	*/
		92	movl SYMBOL_NAME(GDT_base), %edi
		93	addl %ebx, %edi
		94	xorl %ebx, %ebx
		95	movb 7(%edi), %bh
		96	movb 4(%edi), %bl
		97	shl $16, %ebx
		98	movw 2(%edi), %bx
		99	/* Is it correct? I think so... Test it!!! */
		100	addl %ebx, %esp
		101	/* Save EBX for returning to our stack... */
		102	movw %ds, %cx
		103	movw %ss, %dx
		104	movw %cx, %ss
		105	pushl %ebx
		106	pushl %edx
		107	cld
		108	movl SYMBOL_NAME(timermode), %eax
		109	cmpl $1, %eax
		110	je apic_oneshot
		111	call SYMBOL_NAME(periodic_wake_up)
		112	jmp apic_Timer_OK
		113	apic_oneshot: call SYMBOL_NAME(oneshot_wake_up)
		114	apic_Timer_OK:
		115	/* Restore ESP */
		116	popl %edx
		117	popl %ebx /* We must subtract it from ESP...*/
		118	subl %ebx, %esp
		119	movw %dx, %ss
		120
		121	#ifdef __VIRCSW__
		122
		123	movw SYMBOL_NAME(currCtx), %ax
		124	cmpw %ax,JmpSel
		125	je apic_NoPreempt2
		126	movw %ax,JmpSel
		127	ljmp JmpZone /* DISPATCH! */
		128	#endif
		129	apic_NoPreempt2:
		130
		131	cmpl $0, SYMBOL_NAME(last_handler)
		132	je apic_nohandler
		133	movl SYMBOL_NAME(last_handler), %ebx
		134	call *%ebx
		135	apic_nohandler:
305	giacomo	136
		137	sti
		138
299	giacomo	139	popw %gs
		140	popw %fs
		141	popw %es
		142	popw %ds
		143	popal
		144	iret
		145
2	pj	146	.globl SYMBOL_NAME(ll_timer)
		147	/* This is the timer handler; it reloads for safety the DS register; this */
		148	/* prevents from mess when timer interrupts linear access to memory (not in */
		149	/* ELF address space); then EOI is sent in order to detect timer overrun */
		150	/* The high level kernel procedure wake_up() is called to perform the */
		151	/* preeption at higher level (process descriptos); the resulting context */
		152	/* if different from the old one is used to trigger the task activation. */
		153
		154	SYMBOL_NAME_LABEL(ll_timer)
		155	pushal
		156	pushw %ds
		157	pushw %es
		158	pushw %fs
		159	pushw %gs
305	giacomo	160
		161	cli
		162
		163	/* Send ACK to master PIC */
		164	movb $0x20,%al
		165	movl $0x20,%edx
		166	outb %al,%dx
2	pj	167
		168	movw $(X_FLATDATA_SEL),%ax
		169	movw %ax,%ds
		170	movw %ax,%es
		171
		172	/* Call wake_up(actual_context) */
		173
		174	movl SYMBOL_NAME(ll_clock),%eax
		175	incl %eax
		176	movl %eax,SYMBOL_NAME(ll_clock)
		177
		178	/* The following could be optimized a little... */
		179	xorl %ebx, %ebx
		180	movw %ss, %bx
		181	/* We must switch to a ``safe stack'' */
		182	/*
		183	* OK, this is the idea: in %esp we have the address of the
		184	* stack pointer in the APPLICATION address space...
		185	* We assume that address spaces are implemented through segments...
		186	* What we have to do is to add the segment base to %esp:
		187	* - Load the GDT base in a register
		188	* - Add DS * 8 to that value
		189	* - Read the corresponding GDT entry (the segment descriptor)
		190	* - Compute the base...
		191	* It is (p & 0xFC) \| ((p +1) & 0x0F) << 16) \| *(p + 2)
		192	*/
		193	movl SYMBOL_NAME(GDT_base), %edi
		194	addl %ebx, %edi
		195	xorl %ebx, %ebx
		196	movb 7(%edi), %bh
		197	movb 4(%edi), %bl
		198	shl $16, %ebx
		199	movw 2(%edi), %bx
		200	/* Is it correct? I think so... Test it!!! */
		201	addl %ebx, %esp
		202	/* Save EBX for returning to our stack... */
		203	movw %ds, %cx
		204	movw %ss, %dx
		205	movw %cx, %ss
		206	pushl %ebx
		207	pushl %edx
		208	cld
		209	movl SYMBOL_NAME(timermode), %eax
		210	cmpl $1, %eax
		211	je oneshot
		212	call SYMBOL_NAME(periodic_wake_up)
		213	jmp goon
		214	oneshot: call SYMBOL_NAME(oneshot_wake_up)
227	giacomo	215	jmp Timer_OK
2	pj	216	goon:
		217	/* This is the overrun test */
		218	/* Do it after sending EOI to master PIC */
		219
		220	movb $0x0A,%al
		221	movl $0x020,%edx
		222	outb %al,%dx
		223	inb %dx,%al
		224	testb $1,%al
		225	jz Timer_OK
		226	movl $(CLOCK_OVERRUN),%eax
		227	pushl %eax
		228	call SYMBOL_NAME(ll_abort)
		229
		230	Timer_OK:
		231	/* Restore ESP */
		232	popl %edx
		233	popl %ebx /* We must subtract it from ESP...*/
		234	subl %ebx, %esp
		235	movw %dx, %ss
40	pj	236
2	pj	237	#ifdef __VIRCSW__
		238
		239	movw SYMBOL_NAME(currCtx), %ax
		240	cmpw %ax,JmpSel
		241	je NoPreempt2
		242	movw %ax,JmpSel
		243	ljmp JmpZone /* DISPATCH! */
		244	#endif
		245	NoPreempt2:
		246
		247	cmpl $0, SYMBOL_NAME(last_handler)
		248	je nohandler
		249	movl SYMBOL_NAME(last_handler), %ebx
		250	call *%ebx
		251	nohandler:
305	giacomo	252
		253	sti
		254
2	pj	255	popw %gs
		256	popw %fs
		257	popw %es
		258	popw %ds
		259	popal
		260	iret

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(root)/shark/trunk/oslib/kl/timeint.s - Rev 305