tests: check if SSE registers are preserved on context switches

1 files changed, 27 insertions, 0 deletions

diff --git a/src/cmd/tests/kernel/misc.s b/src/cmd/tests/kernel/misc.s
new file mode 100644
index 0000000..ae1b567
--- /dev/null
+++ b/src/cmd/tests/kernel/misc.s
@@ -0,0 +1,27 @@
+.section .text
+.global _sse_test
+.type _sse_test, @function
+
+/* Written in assembly to ensure gcc won't mess with the XMM registers */
+_sse_test:
+	movdqu (%rdi), %xmm1
+	push %rdi /* preserve */
+
+	call fork
+	cmp $0, %rax
+	je child
+
+	/* in parent - wait for the child to die */
+	mov %rax, %rdi
+	mov $0, %rsi
+	mov $0, %rdx
+	call _sys_wait2
+
+	pop %rdi
+	movdqu %xmm1, (%rdi)
+	ret
+
+child:
+	pxor %xmm1, %xmm1
+	mov $0, %rdi
+	call _sys_exit