d0f7acf9eb
An x86-64 operating system built from xv6, now largely rewritten: SMP, a copy-on-write root filesystem (SchFS), PCI/USB/virtio drivers, a TTF rasteriser, and a Linux-numbered syscall ABI. No history before this point -- the tree was never under version control. This commit exists so the rename that follows has something to undo to.
30 lines
510 B
ArmAsm
30 lines
510 B
ArmAsm
# Context switch
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#
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# void swtch(struct context **old, struct context *new);
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#
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# Save current register context in old
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# and then load register context from new.
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.global swtch
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swtch:
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# Save old callee-save registers
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pushq %rbp
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pushq %rbx
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pushq %r12
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pushq %r13
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pushq %r14
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pushq %r15
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# Switch stacks
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movq %rsp, (%rdi)
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movq %rsi, %rsp
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# Load new callee-save registers
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popq %r15
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popq %r14
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popq %r13
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popq %r12
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popq %rbx
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popq %rbp
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retq #??
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