// of constant-sized-frame functions to encode a few bits of size in the pc.
// Caution: ugly multiline assembly macros in your future!

#define DISPATCH(NAME,MAXSIZE)		\
	MOVV	$MAXSIZE, R30;		\
	SGTU	R19, R30, R30;		\
	BNE	R30, 3(PC);			\
	MOVV	$NAME(SB), R4;	\
	JMP	(R4)
// Note: can't just "BR NAME(SB)" - bad inlining results.

TEXT ·reflectcall(SB), NOSPLIT|NOFRAME, $0-48
	MOVWU frameSize+32(FP), R19

	RET

noswitch:
	// already on m stack, just call directly
	// Using a tail call here cleans up tracebacks since we won't stop
	// at an intermediate systemstack.
	MOVD	0(R26), R3	// code pointer
	MOVD.P	16(RSP), R30	// restore LR
	SUB	$8, RSP, R29	// restore FP
	B	(R3)

// func switchToCrashStack0(fn func())
TEXT runtime·switchToCrashStack0<ABIInternal>(SB), NOSPLIT, $0-8
	MOVD	R0, R26    // context register

// The race ctx is passed in R3 and loaded in
// racecalladdr.
//
// The sequence used to get the race ctx:
//    MOVD    runtime·tls_g(SB), R10 // Address of TLS variable
//    MOVD    0(R10), g              // g = R30
//    MOVD    g_racectx(g), R3       // racectx == ThreadState

// func runtime·RaceRead(addr uintptr)
// Called from instrumented Go code
TEXT	runtime·raceread<ABIInternal>(SB), NOSPLIT, $0-8
	MOVD	R3, R4 // addr

	// If no traceback support function, which means that
	// runtime/cgo was not linked in, do usual sigtramp.
	MOVD	_cgo_callers(SB), R6
	CMP	$0, R6
	BEQ	sigtramp

	// Inspect the g in TLS without clobbering R30/R31 via runtime.load_g.
	MOVD	runtime·tls_g(SB), R9
	MOVD	0(R9), R9

	// Figure out if we are currently in a cgo call.
	// If not, just do usual sigtramp.
	// compared to ARM64 and others.
	CMP	$0, R9

	MOVW	$0, R1
	RET

// Called from cgo wrappers, this function returns g->m->curg.stack.hi.
// Must obey the gcc calling convention.
TEXT _cgo_topofstack(SB),NOSPLIT|NOFRAME,$0
	// g (R30), R3 and REGTMP (R23) might be clobbered by load_g. R30 and R23
	// are callee-save in the gcc calling convention, so save them.
	MOVW	R23, R8
	MOVW	g, R9
	MOVW	R31, R10 // this call frame does not save LR

	JAL	runtime·load_g(SB)

	PPC64DWARFRegisters[REG_XER] = 76
}

/*
 * GENERAL:
 *
 * compiler allocates R3 up as temps
 * compiler allocates register variables R7-R27
 * compiler allocates external registers R30 down
 *
 * compiler allocates register variables F17-F26
 * compiler allocates external registers F26 down
 */
const (
	BIG = 32768 - 8
)

const (
	/* mark flags */
	LABEL    = 1 << 0

// Clobbers R19, R20.
TEXT	racecall<>(SB), NOSPLIT|NOFRAME, $0-0
	MOVD	g_m(g), R10
	// Switch to g0 stack.
	MOVD	RSP, R19	// callee-saved, preserved across the CALL
	MOVD	R30, R20	// callee-saved, preserved across the CALL
	MOVD	m_g0(R10), R11
	CMP	R11, g
	BEQ	call	// already on g0
	MOVD	(g_sched+gobuf_sp)(R11), R12
	MOVD	R12, RSP
call:

TEXT __cgo_topofstack(SB),NOSPLIT|NOFRAME,$0
#else
TEXT _cgo_topofstack(SB),NOSPLIT|NOFRAME,$0
#endif
	// g (R30) and R31 are callee-save in the C ABI, so save them
	MOVD	g, R4
	MOVD	R31, R5
	MOVD	LR, R6

	BL	runtime·load_g(SB)	// clobbers g (R30), R31
	MOVD	g_m(g), R3
	MOVD	m_curg(R3), R3
	MOVD	(g_stack+stack_hi)(R3), R3

	MOVD	R4, g
	MOVD	R5, R31
	MOVD	R6, LR