clone

pub fn clone() callconv(.naked) u64

File

Code

pub fn clone() callconv(.naked) u64 {
    // __clone(func, stack, flags, arg, ptid, tls, ctid)
    //         a0,   a1,    a2,    a3,  a4,   a5,  a6
    //
    // syscall(SYS_clone, flags, stack, ptid, tls, ctid)
    //         v0         a0,    a1,    a2,   a3,  a4
    asm volatile (
        \\ # Save function pointer and argument pointer on new thread stack
        \\ and $a1, $a1, -16
        \\ dsubu $a1, $a1, 16
        \\ sd $a0, 0($a1)
        \\ sd $a3, 8($a1)
        \\
        \\ # Shuffle (fn,sp,fl,arg,ptid,tls,ctid) to (fl,sp,ptid,tls,ctid)
        \\ move $a0, $a2
        \\ move $a2, $a4
        \\ move $a3, $a5
        \\ move $a4, $a6
        \\ li $v0, 5055 # SYS_clone
        \\ syscall
        \\ beq $a3, $zero, 1f
        \\ blez $v0, 2f
        \\ dsubu $v0, $zero, $v0
        \\ b 2f
        \\1:
        \\ beq $v0, $zero, 3f
        \\2:
        \\ jr $ra
        \\3:
    );
    if (builtin.unwind_tables != .none or !builtin.strip_debug_info) asm volatile (
        \\ .cfi_undefined $ra
    );
    asm volatile (
        \\ move $fp, $zero
        \\ move $ra, $zero
        \\
        \\ ld $t9, 0($sp)
        \\ ld $a0, 8($sp)
        \\ jalr $t9
        \\
        \\ move $a0, $v0
        \\ li $v0, 5058 # SYS_exit
        \\ syscall
    );
}