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/*
The kernel uses the following registers:
%rdi, %rsi, %rdx, %r8, %r9, %r10
The number of the syscall is passed in %rax.
A syscall clobbers:
%rax, %rcx, %r11
The returned value is placed in %rax.
*/
.text
.globl syscall1
.type syscall1, @function
syscall1:
movq %rsi, %rax // Syscall number.
syscall
ret
.globl syscall2
.type syscall2, @function
syscall2:
// Store registers.
movq %rdi, %r8
movq %rdx, %rax // Syscall number.
// Syscall arguments.
movq %rsi, %rdi
movq %r8, %rsi
syscall
// Restore registers.
movq %rdi, %rsi
movq %r8, %rdi
ret
.globl syscall3
.type syscall3, @function
syscall3:
// Store registers.
movq %rdi, %r8
movq %rcx, %rax // Syscall number.
// Syscall arguments.
movq %rdx, %rdi
movq %r8, %rdx
syscall
// Restore registers.
movq %r8, %rdi
ret
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