MOVV	(g_sched+gobuf_sp)(g), R3

	// Now on a scheduling stack (a pthread-created stack).
g0:
	// Save room for two of our pointers.
	ADDV	$-16, R3
	MOVV	R13, 0(R3)	// save old g on stack
	MOVV	(g_stack+stack_hi)(R13), R13
	SUBVU	R12, R13
	MOVV	R13, 8(R3)	// save depth in old g stack (can't just save SP, as stack might be copied during a callback)
	JAL	(R25)

	// Restore g, stack pointer. R4 is return value.

	MOVQ	g(R12), R14
	MOVQ	g_m(R14), R13
	MOVQ	m_g0(R13), R15
	CMPQ	R13, R15
	JEQ	noswitch	// branch if already on g0
	MOVQ	R15, g(R12)	// g = m->g0
	MOVQ	R15, R14	// set g register
	PUSHQ	RARG1	// func arg
	PUSHQ	RARG0	// func arg
	CALL	runtime·racecallback(SB)
	POPQ	R12
	POPQ	R12
	// All registers are smashed after Go code, reload.
	get_tls(R12)
	MOVQ	g(R12), R13
	MOVQ	g_m(R13), R13

	// load_g will clobber R0, Save R0
	MOVD	R0, R13
	load_g
	// restore R0
	MOVD	R13, R0
	MOVD	g_m(g), R13
	MOVD	m_g0(R13), R14
	CMP	R14, g
	BEQ	noswitch	// branch if already on g0
	MOVD	R14, g

	MOVD	R0, 8(RSP)	// func arg
	MOVD	R1, 16(RSP)	// func arg
	BL	runtime·racecallback(SB)

	// All registers are smashed after Go code, reload.
	MOVD	g_m(g), R13
	MOVD	m_curg(R13), g	// g = m->curg
ret:

	MOVD	R9, R0

	// Now on a scheduling stack (a pthread-created stack).
	// Save room for two of our pointers /*, plus 32 bytes of callee
	// save area that lives on the caller stack. */
	MOVD	RSP, R13
	SUB	$16, R13
	MOVD	R13, RSP
	MOVD	R4, 0(RSP)	// save old g on stack
	MOVD	(g_stack+stack_hi)(R4), R4
	SUB	R2, R4
	MOVD	R4, 8(RSP)	// save depth in old g stack (can't just save SP, as stack might be copied during a callback)

	SizeofIovec           = 0x10
	SizeofMsghdr          = 0x38
	SizeofCmsghdr         = 0x10
)

const (
	SizeofSockFprog = 0x10
)

type PtraceRegs struct {
	R15      uint64
	R14      uint64
	R13      uint64
	R12      uint64
	Rbp      uint64
	Rbx      uint64
	R11      uint64
	R10      uint64
	R9       uint64
	R8       uint64
	Rax      uint64
	Rcx      uint64
	Rdx      uint64

#include "asm_ppc64x.h"

#ifdef GOOS_aix
#define cgoCalleeStackSize 48
#else
#define cgoCalleeStackSize 32
#endif

TEXT runtime·rt0_go(SB),NOSPLIT|TOPFRAME,$0
	// R1 = stack; R3 = argc; R4 = argv; R13 = C TLS base pointer

	// initialize essential registers
	BL	runtime·reginit(SB)

	SUB	$(FIXED_FRAME+16), R1
	MOVD	R2, 24(R1)		// stash the TOC pointer away again now we've created a new frame

// A brief recap of the s390x C calling convention.
// Arguments are passed in R2...R6, the rest is on stack.
// Callee-saved registers are: R6...R13, R15.
// Temporary registers are: R0...R5, R14.

// When calling racecalladdr, R1 is the call target address.

// The race ctx, ThreadState *thr below, is passed in R2 and loaded in racecalladdr.

	"R0", // REGZERO, not used, but simplifies counting in regalloc
	"SP", // REGSP
	"SB", // REGSB
	"R3",
	"R4",
	"R5",
	"R6",
	"R7",
	"R8",
	"R9",
	"R10",
	"R11", // REGCTXT for closures
	"R12",
	"R13", // REGTLS
	"R14",
	"R15",
	"R16",
	"R17",
	"R18",
	"R19",
	"R20",
	"R21",
	"R22",
	"R23",
	"R24",
	"R25",
	"R26",
	"R27",
	"R28",
	"R29",

	MOVW	R3, 12(R29)
	MOVW	R4, 16(R29)
	MOVW	R5, 20(R29)
	MOVW	R6, 24(R29)
	MOVW	R7, 28(R29)
	MOVW	R8, 32(R29)
	MOVW	R9, 36(R29)
	MOVW	R10, 40(R29)
	MOVW	R11, 44(R29)
	MOVW	R12, 48(R29)
	MOVW	R13, 52(R29)
	MOVW	R14, 56(R29)
	MOVW	R15, 60(R29)
	MOVW	R16, 64(R29)
	MOVW	R17, 68(R29)
	MOVW	R18, 72(R29)
	MOVW	R19, 76(R29)
	MOVW	R20, 80(R29)
	// R21 already saved
	// R22 already saved.

	typ   string
	off   int
	size  int
	inner []*asmVar
}

var (
	asmArch386      = asmArch{name: "386", bigEndian: false, stack: "SP", lr: false}
	asmArchArm      = asmArch{name: "arm", bigEndian: false, stack: "R13", lr: true}
	asmArchArm64    = asmArch{name: "arm64", bigEndian: false, stack: "RSP", lr: true, retRegs: []string{"R0", "F0"}}