1 files changed, 58 insertions, 0 deletions
diff --git a/src/runtime/cgo/gcc_s390x.S b/src/runtime/cgo/gcc_s390x.S
new file mode 100644
index 0000000..8bd30fe
--- /dev/null
+++ b/src/runtime/cgo/gcc_s390x.S
@@ -0,0 +1,58 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+.file "gcc_s390x.S"
+
+/*
+ * void crosscall_s390x(void (*fn)(void), void *g)
+ *
+ * Calling into the go tool chain, where all registers are caller save.
+ * Called from standard s390x C ABI, where r6-r13, r15, and f8-f15 are
+ * callee-save, so they must be saved explicitly.
+ */
+.globl crosscall_s390x
+crosscall_s390x:
+	/* save r6-r15 in the register save area of the calling function */
+	stmg    %r6, %r15, 48(%r15)
+
+	/* allocate 64 bytes of stack space to save f8-f15 */
+	lay     %r15, -64(%r15)
+
+	/* save callee-saved floating point registers */
+	std     %f8, 0(%r15)
+	std     %f9, 8(%r15)
+	std     %f10, 16(%r15)
+	std     %f11, 24(%r15)
+	std     %f12, 32(%r15)
+	std     %f13, 40(%r15)
+	std     %f14, 48(%r15)
+	std     %f15, 56(%r15)
+
+	/* restore g pointer */
+	lgr     %r13, %r3
+
+	/* call fn */
+	basr    %r14, %r2
+
+	/* restore floating point registers */
+	ld      %f8, 0(%r15)
+	ld      %f9, 8(%r15)
+	ld      %f10, 16(%r15)
+	ld      %f11, 24(%r15)
+	ld      %f12, 32(%r15)
+	ld      %f13, 40(%r15)
+	ld      %f14, 48(%r15)
+	ld      %f15, 56(%r15)
+
+	/* de-allocate stack frame */
+	la      %r15, 64(%r15)
+
+	/* restore general purpose registers */
+	lmg     %r6, %r15, 48(%r15)
+
+	br      %r14 /* restored by lmg */
+
+#ifdef __ELF__
+.section .note.GNU-stack,"",%progbits
+#endif