// Copyright 2014 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.

//go:build linux && (ppc64 || ppc64le)

.file "gcc_linux_ppc64x.S"

// Define a frame which has no argument space, but is compatible with

// a call into a Go ABI. We allocate 32B to match FIXED_FRAME with

// similar semantics, except we store the backchain pointer, not the

// LR at offset 0. R2 is stored in the Go TOC save slot (offset 24).

.set GPR_OFFSET, 32

.set FPR_OFFSET, GPR_OFFSET + 18*8

.set VR_OFFSET, FPR_OFFSET + 18*8

.set FRAME_SIZE, VR_OFFSET + 12*16

.macro FOR_EACH_GPR opcode r=14

.ifge 31 - \r

\opcode \r, GPR_OFFSET + 8*(\r-14)(1)

FOR_EACH_GPR \opcode "(\r+1)"

.endif

.endm

.macro FOR_EACH_FPR opcode fr=14

.ifge 31 - \fr

\opcode \fr, FPR_OFFSET + 8*(\fr-14)(1)

FOR_EACH_FPR \opcode "(\fr+1)"

.endif

.endm

.macro FOR_EACH_VR opcode vr=20

.ifge 31 - \vr

li 0, VR_OFFSET + 16*(\vr-20)

\opcode \vr, 1, 0

FOR_EACH_VR \opcode "(\vr+1)"

.endif

.endm

/*

* void crosscall_ppc64(void (*fn)(void), void *g)

*

* Calling into the gc tool chain, where all registers are caller save.

* Called from standard ppc64 C ABI, where r2, r14-r31, f14-f31 are

* callee-save, so they must be saved explicitly.

*/

.globl crosscall_ppc64

crosscall_ppc64:

// Start with standard C stack frame layout and linkage

mflr %r0

std %r0, 16(%r1) // Save LR in caller's frame

mfcr %r0

std %r0, 8(%r1) // Save CR in caller's frame

stdu %r1, -FRAME_SIZE(%r1)

std %r2, 24(%r1)

FOR_EACH_GPR std

FOR_EACH_FPR stfd

FOR_EACH_VR stvx

// Set up Go ABI constant registers

li %r0, 0

// Restore g pointer (r30 in Go ABI, which may have been clobbered by C)

mr %r30, %r4

// Call fn

mr %r12, %r3

mtctr %r3

bctrl

FOR_EACH_GPR ld

FOR_EACH_FPR lfd

FOR_EACH_VR lvx

ld %r2, 24(%r1)

addi %r1, %r1, FRAME_SIZE

ld %r0, 16(%r1)

mtlr %r0

ld %r0, 8(%r1)

mtcr %r0

blr

#ifdef __ELF__

.section .note.GNU-stack,"",%progbits

#endif