avoid a register copy when fetching the stack pointer in _start

2019-07-26 09:59:18 +02:00 · 2019-07-26 09:59:18 +02:00 · 74abc5ad2f
parent 9e11f67f0d
commit 74abc5ad2f
1 changed files with 4 additions and 4 deletions
--- a/std/special/start.zig
+++ b/std/special/start.zig
@ -35,13 +35,13 @@ nakedcc fn _start() noreturn {

    switch (builtin.arch) {
        .x86_64 => {
-            argc_ptr = asm ("lea (%%rsp), %[argc]"
-                : [argc] "=r" (-> [*]usize)
+            argc_ptr = asm (""
+                : [argc] "={rsp}" (-> [*]usize)
            );
        },
        .i386 => {
-            argc_ptr = asm ("lea (%%esp), %[argc]"
-                : [argc] "=r" (-> [*]usize)
+            argc_ptr = asm (""
+                : [argc] "={esp}" (-> [*]usize)
            );
        },
        .aarch64, .aarch64_be => {