36 lines
631 B
ArmAsm
36 lines
631 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 the current registers on the stack, creating
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# a struct context, and save its address in *old.
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# Switch stacks to new and pop previously-saved registers.
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.globl swtch
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swtch:
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# Save old callee-saved registers
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push %rbp
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push %rbx
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push %r11
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push %r12
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push %r13
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push %r14
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push %r15
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# Switch stacks
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mov %rsp, (%rdi) # first arg of swtch is in rdi
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mov %rsi, %rsp # second arg of swtch is in rsi
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# Load new callee-saved registers
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pop %r15
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pop %r14
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pop %r13
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pop %r12
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pop %r11
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pop %rbx
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pop %rbp
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ret
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