47 lines
985 B
ArmAsm
47 lines
985 B
ArmAsm
.globl task_switch
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// This function takes a pointer
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// to a PROC structure and jump
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// to this process
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task_switch:
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pop %esi
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push 8(%esi) # eax (cf PROC struct)
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push 12(%esi) # ebx
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push 16(%esi) # ecx
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push 20(%esi) # edx
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push 40(%esi) # ebp
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push 48(%esi) # edi
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push 52(%esi) # ds
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push 56(%esi) # es
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push 60(%esi) # fs
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push 64(%esi) # gs
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// Don't forget to clear the interrupt
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movb $0x20, %al
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outb %al, $0x20
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// Setup process page directory
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mov 4(%esi), %eax
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mov %eax, %cr3
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// Setup registers
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pop %gs
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pop %fs
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pop %es
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pop %ds
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pop %edi
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pop %ebp
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pop %edx
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pop %ecx
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pop %ebx
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pop %eax
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// Perform the task switch
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push 32(%esi) # ss
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push 36(%esi) # esp
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push 68(%esi) # eflags
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push 24(%esi) # cs
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push 28(%esi) # eip
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mov 52(%esi), %ds # Choose the right data segment
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mov 44(%esi), %esi # Now restore task esi
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iret # Launch task
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