1// Copyright 2016 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5.file "gcc_s390x.S"
6
7/*
8 * void crosscall1(void (*fn)(void), void (*setg_gcc)(void*), void *g)
9 *
10 * Calling into the go tool chain, where all registers are caller save.
11 * Called from standard s390x C ABI, where r6-r13, r15, and f8-f15 are
12 * callee-save, so they must be saved explicitly.
13 * ABI: r2=fn, r3=setg_gcc, r4=g.
14 */
15.globl crosscall1
16crosscall1:
17 /* save r6-r15 in the register save area of the calling function */
18 stmg %r6, %r15, 48(%r15)
19
20 /* allocate 64 bytes of stack space to save f8-f15 */
21 lay %r15, -64(%r15)
22
23 /* save callee-saved floating point registers */
24 std %f8, 0(%r15)
25 std %f9, 8(%r15)
26 std %f10, 16(%r15)
27 std %f11, 24(%r15)
28 std %f12, 32(%r15)
29 std %f13, 40(%r15)
30 std %f14, 48(%r15)
31 std %f15, 56(%r15)
32
33 /* save fn pointer in r6 (already saved to stack) */
34 lgr %r6, %r2
35 /* restore g pointer */
36 lgr %r13, %r4
37
38 /* prepare arg for setg_gcc: first argument in r2 */
39 lgr %r2, %r4 /* r2 = g */
40 /* call setg_gcc(g) using function pointer in r3 */
41 basr %r14, %r3
42
43 /* call fn */
44 lgr %r2, %r6
45 basr %r14, %r2
46
47 /* restore floating point registers */
48 ld %f8, 0(%r15)
49 ld %f9, 8(%r15)
50 ld %f10, 16(%r15)
51 ld %f11, 24(%r15)
52 ld %f12, 32(%r15)
53 ld %f13, 40(%r15)
54 ld %f14, 48(%r15)
55 ld %f15, 56(%r15)
56
57 /* de-allocate stack frame */
58 la %r15, 64(%r15)
59
60 /* restore general purpose registers */
61 lmg %r6, %r15, 48(%r15)
62
63 br %r14 /* restored by lmg */
64
65#ifdef __ELF__
66.section .note.GNU-stack,"",%progbits
67#endif
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