1 files changed, 33 insertions, 0 deletions
diff --git a/usr/klibc/arch/alpha/sysdual.S b/usr/klibc/arch/alpha/sysdual.S
new file mode 100644
index 0000000..03e719d
--- /dev/null
+++ b/usr/klibc/arch/alpha/sysdual.S
@@ -0,0 +1,33 @@
+#
+# arch/alpha/sysdual.S
+#
+
+#
+# Some system calls have an alternate return value in r20 (a4).
+# This system call stub is for system calls where that is
+# the "real" return value.
+#
+
+#include <machine/asm.h>
+
+	.text
+	.align	3
+	.type	__syscall_dual1,@function
+	.ent	__syscall_dual1, 0
+	.globl	__syscall_dual1
+__syscall_dual1:
+	.frame	sp,0,ra,0
+	callsys
+	beq	a3, 1f
+	br	pv, 2f			# pv <- pc
+2:
+	ldgp	gp, 0(pv)
+	lda	a1, errno
+	stl	v0, 0(a1)
+	lda	a4, -1(zero)
+1:
+	mov	a4, v0
+	ret	zero,(ra),1
+
+	.size	__syscall_dual1,.-__syscall_dual1
+	.end	__syscall_dual1