// Only valid on functions that declare a frame size of 0.
#define NOFRAME 512
// Function can call reflect.Type.Method or reflect.Type.MethodByName.
#define REFLECTMETHOD 1024
// Function is the outermost frame of the call stack. Call stack unwinders
// should stop at this function.
#define TOPFRAME 2048
// Function is an ABI wrapper.

	// TODO(mwhudson): only implemented for ppc64x at present.
	NOFRAME = 512

	// Function can call reflect.Type.Method or reflect.Type.MethodByName.
	REFLECTMETHOD = 1024

	// Function is the outermost frame of the call stack. Call stack unwinders
	// should stop at this function.
	TOPFRAME = 2048

	// Function is an ABI wrapper.
	ABIWRAPPER = 4096

ok:
	MOVW	R0, ret+8(FP)
	RET

TEXT runtime·read(SB),NOSPLIT|NOFRAME,$0
	MOVW	fd+0(FP), R0		// arg 1 - fd
	MOVD	p+8(FP), R1		// arg 2 - buf
	MOVW	n+16(FP), R2		// arg 3 - count
	SVC	$SYS_read
	BCC	ok
	NEG	R0, R0
ok:
	MOVW	R0, ret+24(FP)
	RET

// func pipe2(flags int32) (r, w int32, errno int32)
TEXT runtime·pipe2(SB),NOSPLIT|NOFRAME,$0-20
	ADD	$16, RSP, R0
	MOVW	flags+0(FP), R1
	SVC	$SYS_pipe2

const (
	// FuncFlagTopFrame indicates a function that appears at the top of its stack.
	// The traceback routine stop at such a function and consider that a
	// successful, complete traversal of the stack.
	// Examples of TopFrame functions include goexit, which appears
	// at the top of a user goroutine stack, and mstart, which appears
	// at the top of a system goroutine stack.
	FuncFlagTopFrame FuncFlag = 1 << iota

	MOVL	CX, 4(SP)
	MOVL	DX, 8(SP)
	MOVL	SI, 12(SP)	// save SI: handler might be a Go function
	CALL	AX
	MOVL	12(SP), AX
	MOVL	AX, SP
	RET

// Called by OS using C ABI.
TEXT runtime·sigtramp(SB),NOSPLIT|TOPFRAME,$28
	NOP	SP	// tell vet SP changed - stop checking offsets
	// Save callee-saved C registers, since the caller may be a C signal handler.
	MOVL	BX, bx-4(SP)
	MOVL	BP, bp-8(SP)
	MOVL	SI, si-12(SP)

GLOBL	runtime·sigtramp(SB), NOPTR, $24

// This function must not have any frame as we want to control how
// every registers are used.
// TODO(aix): Implement SetCgoTraceback handler.
TEXT sigtramp<>(SB),NOSPLIT|NOFRAME|TOPFRAME,$0
	MOVD	LR, R0
	MOVD	R0, 16(R1)
	// initialize essential registers (just in case)
	BL	runtime·reginit(SB)

	// Note that we are executing on altsigstack here, so we have

	XORL	AX, AX			// return 0 == success
	MOVL	AX, ret+8(FP)
	RET

// Careful, this is called by __sighndlr, a libc function. We must preserve
// registers as per AMD 64 ABI.
TEXT runtime·sigtramp(SB),NOSPLIT|TOPFRAME|NOFRAME,$0
	// Note that we are executing on altsigstack here, so we have
	// more stack available than NOSPLIT would have us believe.
	// To defeat the linker, we make our own stack frame with
	// more space:

	MOVD	$2, R8	// crash (not reached)
	MOVD	R8, (R8)
	RET

// func exit(code int32)
TEXT runtime·exit(SB),NOSPLIT|NOFRAME,$0-4
	MOVW	code+0(FP), R0
	MOVD	$SYS_exit, R8
	SVC
	MOVD	$0, R0
	MOVD	R0, (R0)

// func exitThread(wait *atomic.Uint32)
TEXT runtime·exitThread(SB),NOSPLIT|NOFRAME,$0-8
	MOVD	wait+0(FP), R0
	// We're done using the stack.
	MOVW	$0, R1
	STLRW	R1, (R0)
	MOVW	$0, R0

	MOVV	R2, (R2)
	JMP	0(PC)

TEXT runtime·open(SB),NOSPLIT|NOFRAME,$0
	MOVV	name+0(FP), R4		// arg 1 - path
	MOVW	mode+8(FP), R5		// arg 2 - mode
	MOVW	perm+12(FP), R6		// arg 3 - perm
	MOVV	$5, R2			// sys_open
	SYSCALL
	BEQ	R7, 2(PC)
	MOVW	$-1, R2
	MOVW	R2, ret+16(FP)
	RET

TEXT runtime·closefd(SB),NOSPLIT|NOFRAME,$0
	MOVW	fd+0(FP), R4		// arg 1 - fd
	MOVV	$6, R2			// sys_close
	SYSCALL

	MOVL	CX, 4(SP)
	MOVL	DX, 8(SP)
	MOVL	SI, 12(SP)	// save SI: handler might be a Go function
	CALL	AX
	MOVL	12(SP), AX
	MOVL	AX, SP
	RET

// Called by OS using C ABI.
TEXT runtime·sigtramp(SB),NOSPLIT|TOPFRAME,$12
	NOP	SP	// tell vet SP changed - stop checking offsets
	MOVL	16(SP), BX	// signo
	MOVL	BX, 0(SP)
	MOVL	20(SP), BX // info
	MOVL	BX, 4(SP)
	MOVL	24(SP), BX // context
	MOVL	BX, 8(SP)