#
# Copyright (C) 2003, 2004 Robert Lougher <rob@lougher.demon.co.uk>.
#
# This file is part of JamVM.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2,
# or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#

	.text
	.align	2
	.global	callJNIMethod
	.type	callJNIMethod,function
callJNIMethod:
	mov	ip, sp
	stmfd	sp!, {r4, r5, ip, lr}
        mov	r4, ip
        mov     r5, r3			@ save native_arg
	ldr     ip, [r4] 		@ get ostack pntr
        ldr	r2, [r4, #8]		@ get args_count
	cmp	r1, #0     		@ is method static? 
	ldreq	r1, [ip], #4 		@ no, load r0 with "this"
	addne	r2, r2, #1		@ yes, add 1 to cnt for "class" 
	subs	r2, r2, #3		@ no. of args fit in registers?
	ble	do_call			@ yes, skip stack push
	add	lr, ip, #4

	@ loop pushing extra args from ostack
	@ onto native stack.
	@ lr = ostack pntr, r2 = loop counter
loop:
	ldr	r3, [lr, r2, lsl #2]
	str	r3, [sp, #-4]!
	subs	r2, r2, #1
	bne	loop

do_call:
	@ load last two registers in calling
	@ convention.  Doesn't matter if args < 4,
	@ faster than checking and safe to load rubbish

	ldr	r2, [ip]
	ldr	r3, [ip, #4]

	mov	lr, pc
	ldr	pc, [r4, #4]		@ call the function...

	@ reload ostack pntr for pushing return value
	ldr     r2, [r4]

	@ native_arg holds return type (set in nativeExtraArg)
	@ 0 = void, 1 = double, 2 = float, 3 = long
	@ 4 = everything else

	@ values arranged so that if it's >= 3, it's "int" or
	@ long, so push low word - r0 is now free so we can
	@ put opntr into it, for all types

	cmp	r5, #3
	strge	r0, [r2], #4
	mov	r0, r2

	@ optimise for most often case of "int" return - all others
	@ jump to 2 instruction "handler", but this falls through

	addle	pc, pc, r5, lsl #3

	@ room for one instruction here - enough to just return, all
	@ we need, as everything's been done above

	ldmdb	r4, {r4, r5, sp, pc}
	
	@ void return
	ldmdb	r4, {r4, r5, sp, pc}
	nop
	
	@ double return
	nop
	nop

	@ float return
	nop
	nop

	@long return
	str	r1, [r0], #4
	ldmdb	r4, {r4, r5, sp, pc}