/* HImode div/mod functions for the GCC support library for the Renesas RL78 processors.
   Copyright (C) 2012,2013 Free Software Foundation, Inc.
   Contributed by Red Hat.

   This file is part of GCC.

   GCC 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 3, or (at your option)
   any later version.

   GCC 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.

   Under Section 7 of GPL version 3, you are granted additional
   permissions described in the GCC Runtime Library Exception, version
   3.1, as published by the Free Software Foundation.

   You should have received a copy of the GNU General Public License and
   a copy of the GCC Runtime Library Exception along with this program;
   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
   <http://www.gnu.org/licenses/>.  */

#ifndef __RL78_G10__

#include "vregs.h"

	.macro make_generic  which,need_result

	.if \need_result
	quot = r8
	num = r10
	den = r12
	bit = r14
	.else
	num = r8
	quot = r10
	den = r12
	bit = r14
	.endif

	quotB0 = quot
	quotB1 = quot+1
	
	numB0 = num
	numB1 = num+1
	
	denB0 = den
	denB1 = den+1
	
	bitB0 = bit
	bitB1 = bit+1

#if 1
#define bit	bc
#define bitB0	c
#define bitB1	b
#endif

num_lt_den\which:
	.if \need_result
	movw	r8, #0
	.else
	movw	ax, [sp+8]
	movw	r8, ax
	.endif
	ret

	;; These routines leave DE alone - the signed functions use DE
	;; to store sign information that must remain intact

	.if \need_result

generic_div:

	.else

generic_mod:

	.endif

	;; (quot,rem) = 8[sp] /% 10[sp]

	movw	hl, sp
	movw	ax, [hl+10] ; denH
	cmpw	ax, [hl+8] ; numH
	bh	$num_lt_den\which

	;; (quot,rem) = 16[sp] /% 20[sp]

	;; copy numerator
	movw	ax, [hl+8]
	movw	num, ax

	;; copy denomonator
	movw	ax, [hl+10]
	movw	den, ax

	movw	ax, den
	cmpw	ax, #0
	bnz	$den_not_zero\which
	movw	num, #0
	ret

den_not_zero\which:
	.if \need_result
	;; zero out quot
	movw	quot, #0
	.endif

	;; initialize bit to 1
	movw	bit, #1

; while (den < num && !(den & (1L << BITS_MINUS_1)))

shift_den_bit\which:	
	movw	ax, den
	mov1	cy,a.7
	bc	$enter_main_loop\which
	cmpw	ax, num
	bh	$enter_main_loop\which

	;; den <<= 1
;	movw	ax, den		; already has it from the cmpw above
	shlw	ax, 1
	movw	den, ax

	;; bit <<= 1
	.if \need_result
#ifdef bit
	shlw	bit, 1
#else
	movw	ax, bit
	shlw	ax, 1
	movw	bit, ax
#endif
	.else
	;; if we don't need to compute the quotent, we don't need an
	;; actual bit *mask*, we just need to keep track of which bit
	inc	bitB0
	.endif

	br	$shift_den_bit\which

main_loop\which:

	;; if (num >= den) (cmp den > num)
	movw	ax, den
	cmpw	ax, num
	bh	$next_loop\which

	;; num -= den
	movw	ax, num
	subw	ax, den
	movw	num, ax

	.if \need_result
	;; res |= bit
	mov	a, quotB0
	or	a, bitB0
	mov	quotB0, a
	mov	a, quotB1
	or	a, bitB1
	mov	quotB1, a
	.endif

next_loop\which:	

	;; den >>= 1
	movw	ax, den
	shrw	ax, 1
	movw	den, ax

	.if \need_result
	;; bit >>= 1
	movw	ax, bit
	shrw	ax, 1
	movw	bit, ax
	.else
	dec	bitB0
	.endif

enter_main_loop\which:
	.if \need_result
	movw	ax, bit
	cmpw	ax, #0
	.else
	cmp0	bitB0
	.endif
	bnz	$main_loop\which

main_loop_done\which:	
	ret
	.endm

	make_generic _d 1
	make_generic _m 0

;----------------------------------------------------------------------

	.global	___udivhi3
	.type	___udivhi3,@function
___udivhi3:
	;; r8 = 4[sp] / 6[sp]
	call	$!generic_div
	ret
	.size	___udivhi3, . - ___udivhi3
	

	.global	___umodhi3
	.type	___umodhi3,@function
___umodhi3:
	;; r8 = 4[sp] % 6[sp]
	call	$!generic_mod
	ret
	.size	___umodhi3, . - ___umodhi3

;----------------------------------------------------------------------

	.macro neg_ax
	movw	hl, ax
	movw	ax, #0
	subw	ax, [hl]
	movw	[hl], ax
	.endm

	.global	___divhi3
	.type	___divhi3,@function
___divhi3:
	;; r8 = 4[sp] / 6[sp]
	movw	de, #0
	mov	a, [sp+5]
	mov1	cy, a.7
	bc	$div_signed_num
	mov	a, [sp+7]
	mov1	cy, a.7
	bc	$div_signed_den
	call	$!generic_div
	ret
	
div_signed_num:
	;; neg [sp+4]
	movw	ax, sp
	addw	ax, #4
	neg_ax
	mov	d, #1
	mov	a, [sp+7]
	mov1	cy, a.7
	bnc	$div_unsigned_den
div_signed_den:	
	;; neg [sp+6]
	movw	ax, sp
	addw	ax, #6
	neg_ax
	mov	e, #1
div_unsigned_den:	
	call	$!generic_div

	mov	a, d
	cmp0	a
	bz	$div_skip_restore_num
	;;  We have to restore the numerator [sp+4]
	movw	ax, sp
	addw	ax, #4
	neg_ax
	mov	a, d
div_skip_restore_num:	
	xor	a, e
	bz	$div_no_neg
	movw	ax, #r8
	neg_ax
div_no_neg:
	mov	a, e
	cmp0	a
	bz	$div_skip_restore_den
	movw	ax, sp
	addw	ax, #6
	neg_ax
div_skip_restore_den:	
	ret
	.size	___divhi3, . - ___divhi3
	

	.global	___modhi3
	.type	___modhi3,@function
___modhi3:
	;; r8 = 4[sp] % 6[sp]
	movw	de, #0
	mov	a, [sp+5]
	mov1	cy, a.7
	bc	$mod_signed_num
	mov	a, [sp+7]
	mov1	cy, a.7
	bc	$mod_signed_den
	call	$!generic_mod
	ret
	
mod_signed_num:
	;; neg [sp+4]
	movw	ax, sp
	addw	ax, #4
	neg_ax
	mov	d, #1
	mov	a, [sp+7]
	mov1	cy, a.7
	bnc	$mod_unsigned_den
mod_signed_den:	
	;; neg [sp+6]
	movw	ax, sp
	addw	ax, #6
	neg_ax
mod_unsigned_den:	
	call	$!generic_mod

	mov	a, d
	cmp0	a
	bz	$mod_no_neg
	movw	ax, #r8
	neg_ax
	;;  Also restore numerator
	movw 	ax, sp
	addw	ax, #4
	neg_ax
mod_no_neg:
	mov	a, e
	cmp0	a
	bz	$mod_skip_restore_den
	movw	ax, sp
	addw	ax, #6
	neg_ax
mod_skip_restore_den:	
	ret
	.size	___modhi3, . - ___modhi3

#endif