gcc_linux_ppc64x.S

Documentation: runtime/cgo

     1// Copyright 2014 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//go:build linux && (ppc64 || ppc64le)
     6
     7.file "gcc_linux_ppc64x.S"
     8
     9// Define a frame which has no argument space, but is compatible with
    10// a call into a Go ABI. We allocate 32B to match FIXED_FRAME with
    11// similar semantics, except we store the backchain pointer, not the
    12// LR at offset 0. R2 is stored in the Go TOC save slot (offset 24).
    13.set GPR_OFFSET, 32
    14.set FPR_OFFSET, GPR_OFFSET + 18*8
    15.set VR_OFFSET, FPR_OFFSET + 18*8
    16.set FRAME_SIZE, VR_OFFSET + 12*16
    17
    18.macro FOR_EACH_GPR opcode r=14
    19.ifge 31 - \r
    20	\opcode \r, GPR_OFFSET + 8*(\r-14)(1)
    21	FOR_EACH_GPR \opcode "(\r+1)"
    22.endif
    23.endm
    24
    25.macro FOR_EACH_FPR opcode fr=14
    26.ifge 31 - \fr
    27	\opcode \fr, FPR_OFFSET + 8*(\fr-14)(1)
    28	FOR_EACH_FPR \opcode "(\fr+1)"
    29.endif
    30.endm
    31
    32.macro FOR_EACH_VR opcode vr=20
    33.ifge 31 - \vr
    34	li 0, VR_OFFSET + 16*(\vr-20)
    35	\opcode \vr, 1, 0
    36	FOR_EACH_VR \opcode "(\vr+1)"
    37.endif
    38.endm
    39
    40/*
    41 * void crosscall_ppc64(void (*fn)(void), void *g)
    42 *
    43 * Calling into the gc tool chain, where all registers are caller save.
    44 * Called from standard ppc64 C ABI, where r2, r14-r31, f14-f31 are
    45 * callee-save, so they must be saved explicitly.
    46 */
    47.globl crosscall_ppc64
    48crosscall_ppc64:
    49	// Start with standard C stack frame layout and linkage
    50	mflr	%r0
    51	std	%r0, 16(%r1)	// Save LR in caller's frame
    52	mfcr	%r0
    53	std	%r0, 8(%r1)	// Save CR in caller's frame
    54	stdu	%r1, -FRAME_SIZE(%r1)
    55	std	%r2, 24(%r1)
    56
    57	FOR_EACH_GPR std
    58	FOR_EACH_FPR stfd
    59	FOR_EACH_VR stvx
    60
    61	// Set up Go ABI constant registers
    62	li	%r0, 0
    63
    64	// Restore g pointer (r30 in Go ABI, which may have been clobbered by C)
    65	mr	%r30, %r4
    66
    67	// Call fn
    68	mr	%r12, %r3
    69	mtctr	%r3
    70	bctrl
    71
    72	FOR_EACH_GPR ld
    73	FOR_EACH_FPR lfd
    74	FOR_EACH_VR lvx
    75
    76	ld	%r2, 24(%r1)
    77	addi	%r1, %r1, FRAME_SIZE
    78	ld	%r0, 16(%r1)
    79	mtlr	%r0
    80	ld	%r0, 8(%r1)
    81	mtcr	%r0
    82	blr
    83
    84#ifdef __ELF__
    85.section .note.GNU-stack,"",%progbits
    86#endif
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