From 2a155d75ac575c9a99918569249aecdf251e94d9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alex=20R=C3=B8nne=20Petersen?= <alex@alexrp.com>
Date: Sat, 8 Aug 2026 03:19:47 +0200
Subject: [PATCH] std: fix stack alignment in or1k _start and clone assembly

l.andi zero-extends its operand so this would give the wrong result. Instead,
use l.addi to materialize -4 and then l.and that.

Rather unfortunate that the assembler doesn't reject this form.
---
 lib/std/os/linux/or1k.zig | 3 ++-
 lib/std/start.zig         | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/lib/std/os/linux/or1k.zig b/lib/std/os/linux/or1k.zig
index 75dbef7623a4012cca599fd2d49cd3e9d49a6dcc..a54b9bd43ff5464c29d920d222c4988440a267d7 100644
--- a/lib/std/os/linux/or1k.zig
+++ b/lib/std/os/linux/or1k.zig
@@ -124,7 +124,8 @@ pub fn clone() callconv(.naked) u32 {
     //         r11        r3,    r4,    r5,   r6,  r7
     asm volatile (
         \\ # Save function pointer and argument pointer on new thread stack
-        \\ l.andi r4, r4, -4
+        \\ l.addi r13, r0, -4
+        \\ l.and r4, r4, r13
         \\ l.addi r4, r4, -8
         \\ l.sw 0(r4), r3
         \\ l.sw 4(r4), r6
diff --git a/lib/std/start.zig b/lib/std/start.zig
index 0e88eed1a478b09afc6490acffa9fca4c01b1fe2..c49453246fcc59f09d717fe08a9d000a418cd891 100644
--- a/lib/std/start.zig
+++ b/lib/std/start.zig
@@ -326,7 +326,8 @@ fn _start() callconv(.naked) noreturn {
             \\ l.ori r2, r0, 0
             \\ l.ori r9, r0, 0
             \\ l.ori r3, r1, 0
-            \\ l.andi r1, r1, -4
+            \\ l.addi r13, r0, -4
+            \\ l.and r1, r1, r13
             \\ l.j %[posixCallMainAndExit]
             \\  l.nop
             ,
-- 
2.54.0