
#include <sys/regdef.h>
#include <sys/asm.h>

.text
.globl  invoke_count_words
.globl	invoke_copy_to_stack 

LOCALSZ=7		# a0, a1, a2, a3, s0, ra, gp
FRAMESZ=(((NARGSAVE+LOCALSZ)*SZREG)+ALSZ)&ALMASK

RAOFF=FRAMESZ-(1*SZREG)
A0OFF=FRAMESZ-(2*SZREG)
A1OFF=FRAMESZ-(3*SZREG)
A2OFF=FRAMESZ-(4*SZREG)
A3OFF=FRAMESZ-(5*SZREG)
S0OFF=FRAMESZ-(6*SZREG)
GPOFF=FRAMESZ-(7*SZREG)

	#	
	# _XPTC_InvokeByIndex(that, methodIndex, paramCount, params)
	#                      a0       a1          a2         a3

NESTED(_XPTC_InvokeByIndex, FRAMESZ, ra)
	SETUP_GP
	PTR_SUBU sp, FRAMESZ
	SETUP_GP64(GPOFF, _XPTC_InvokeByIndex)
	SAVE_GP(GPOFF)

	REG_S	ra, RAOFF(sp)
	REG_S	a0, A0OFF(sp)
	REG_S	a1, A1OFF(sp)
	REG_S	a2, A2OFF(sp)
	REG_S	a3, A3OFF(sp)
	REG_S	s0, S0OFF(sp)
	REG_S	gp, GPOFF(sp)

	# invoke_count_words(paramCount, params)
        move    a0, a2
	move    a1, a3	
        jal     invoke_count_words

	# invoke_copy_to_stack(PRUint32* d, PRUint32 paramCount,
	#                      nsXPTCVariant* s, PRUint32 *reg)

	REG_L   a1, A2OFF(sp)   # a1 - paramCount
	REG_L	a2, A3OFF(sp)	# a2 - params

	# save sp before we copy the params to the stack
	move	t0, sp

	# assume full size of 8 bytes per param to be safe
	sll	v0, 4		# 8 bytes * num params
	subu	sp, sp, v0	# make room
	move	a0, sp		# a0 - param stack address

	# create temporary stack space to write int and fp regs
        subu    sp, 64          # 64 = 8 regs of 8 bytes

	move    a3, sp

	# save the old sp and save the arg stack
	subu	sp, sp, 16
	REG_S	t0, 0(sp)
	REG_S	a0, 8(sp)

	# copy the param into the stack areas
	jal	invoke_copy_to_stack

	REG_L	t3, 8(sp)	# get previous a0
	REG_L	sp, 0(sp)	# get orig sp back

	REG_L	a0, A0OFF(sp)	# a0 - that
	REG_L	a1, A1OFF(sp)	# a1 - methodIndex

	# t1 = methodIndex * 12
	# (use shift and subtract trick instead of mult)
 	sll	t1, a1, 2
	subu	t1, t1, a1
	sll	t1, t1, 2

	# calculate the function we need to jump to,
	# which must then be saved in t9
	lw	t9, 0(a0)
	addu	t9, t9, t1
	li	t2, 20
	addu	t9, t9, t2
	lw	t9, 0(t9)	# t9 = *(that+t1+20)	

	# calculate the proper "this" pointer for the
	# function that they asked for
	lw	t0, 0(a0)
	addu	t0, t1
	lw	t0, 12(t0)
	addu	a0, a0, t0

	# get register save area from invoke_copy_to_stack
	subu	t1, t3, 64

	# a1..a7 and f13..f19 should now be set to what
	# invoke_copy_to_stack told us. skip a0 and f12
	# because that's the "this" pointer

	REG_L	a1,  0(t1)
	REG_L	a2,  8(t1)
	REG_L	a3, 16(t1)
	REG_L	a4, 24(t1)
	REG_L	a5, 32(t1)
	REG_L	a6, 40(t1)
	REG_L	a7, 48(t1)

	l.d	$f13,  0(t1)
	l.d	$f14,  8(t1)
	l.d	$f15, 16(t1)
	l.d	$f16, 24(t1)
	l.d	$f17, 32(t1)
	l.d	$f18, 40(t1)
	l.d	$f19, 48(t1)

	# save away our stack pointer and create
	# the stack pointer for the function
	move	s0, sp
	move	sp, t3

	jalr	ra, t9

	move	sp, s0

	RESTORE_GP64
	REG_L	ra, RAOFF(sp)
	REG_L	s0, S0OFF(sp)
	PTR_ADDU	sp, FRAMESZ
	j	ra
.end _XPTC_InvokeByIndex
