2020-04-23 00:49:09 +02:00
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.file "irq_pit.S"
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.text
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2020-04-23 23:40:16 +02:00
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.extern switchKthread
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2020-04-23 00:49:09 +02:00
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.globl pit_handler
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.type pit_handler, @function
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pit_handler: // already got eflags, cs and eip on stack thanks to CPU
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pushl $0 // err_code esp+12+8*4=44
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pushal // (general reg) esp+12
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subl $2, %esp // (alignment) esp+10
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pushw %ss // esp+8
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pushw %ds // esp+6
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pushw %es // esp+4
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pushw %fs // esp+2
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pushw %gs // esp
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/* Send EOI to PIC */
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movb $0x20, %al
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outb %al, $0x20
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pushl %esp
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2020-04-23 23:40:16 +02:00
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call switchKthread
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2020-04-23 00:49:09 +02:00
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movl %eax,%esp
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/* Restore the CPU context */
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popw %gs
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popw %fs
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popw %es
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popw %ds
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popw %ss
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addl $2,%esp
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popal
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addl $4, %esp /* Ignore "error code" */
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/* This restores the eflags, the cs and the eip registers */
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iret /* equivalent to: popfl ; ret */
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