win_probe_stack_only

fn win_probe_stack_only() void

File

Code

fn win_probe_stack_only() void {
    @setRuntimeSafety(false);

    switch (arch) {
        .thumb => {
            asm volatile (
                \\ lsl r4, r4, #2
                \\ mov r12, sp
                \\ push {r5, r6}
                \\ mov r5, r4
                \\1:
                \\ sub r12, r12, #4096
                \\ subs r5, r5, #4096
                \\ ldr r6, [r12]
                \\ bgt 1b
                \\ pop {r5, r6}
                \\ bx lr
            );
        },
        .aarch64 => {
            asm volatile (
                \\        lsl    x16, x15, #4
                \\        mov    x17, sp
                \\1:
                \\
                \\        sub    x17, x17, 4096
                \\        subs   x16, x16, 4096
                \\        ldr    xzr, [x17]
                \\        b.gt   1b
                \\
                \\        ret
            );
        },
        .x86_64 => {
            asm volatile (
                \\         pushq  %%rcx
                \\         pushq  %%rax
                \\         cmpq   $0x1000,%%rax
                \\         leaq   24(%%rsp),%%rcx
                \\         jb     1f
                \\ 2:
                \\         subq   $0x1000,%%rcx
                \\         testq  %%rcx,(%%rcx)
                \\         subq   $0x1000,%%rax
                \\         cmpq   $0x1000,%%rax
                \\         ja     2b
                \\ 1:
                \\         subq   %%rax,%%rcx
                \\         testq  %%rcx,(%%rcx)
                \\         popq   %%rax
                \\         popq   %%rcx
                \\         retq
            );
        },
        .x86 => {
            asm volatile (
                \\         push   %%ecx
                \\         push   %%eax
                \\         cmp    $0x1000,%%eax
                \\         lea    12(%%esp),%%ecx
                \\         jb     1f
                \\ 2:
                \\         sub    $0x1000,%%ecx
                \\         test   %%ecx,(%%ecx)
                \\         sub    $0x1000,%%eax
                \\         cmp    $0x1000,%%eax
                \\         ja     2b
                \\ 1:
                \\         sub    %%eax,%%ecx
                \\         test   %%ecx,(%%ecx)
                \\         pop    %%eax
                \\         pop    %%ecx
                \\         ret
            );
        },
        else => {},
    }

    unreachable;
}