/* QImode 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

#if 1
#define bit	b
#define den	c
#define bitden	bc
#endif

num_lt_den\which:
	.if \need_result
	mov	r8, #0
	.else
	mov	a, [hl+4]
	mov	r8, a
	.endif
	ret

num_eq_den\which:
	.if \need_result
	mov	r8, #1
	.else
	mov	r8, #0
	.endif
	ret
	
den_is_zero\which:
	mov	r8, #0xff
	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) = 4[hl] /% 6[hl]

	mov	a, [hl+4] ; num
	cmp	a, [hl+6] ; den
	bz	$num_eq_den\which
	bnh	$num_lt_den\which
	
	;; copy numerator
;	mov	a, [hl+4]	; already there from above
	mov	num, a

	;; copy denomonator
	mov	a, [hl+6]
	mov	den, a

	cmp0	den
	bz	$den_is_zero\which

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

	;; initialize bit to 1
	mov	bit, #1

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

shift_den_bit\which:
	.macro	sdb_one\which
	mov	a, den
	mov1	cy,a.7
	bc	$enter_main_loop\which
	cmp	a, num
	bh	$enter_main_loop\which

	;; den <<= 1
;	mov	a, den		; already has it from the cmpw above
	shl	a, 1
	mov	den, a

	;; bit <<= 1
	shl	bit, 1
	.endm

	sdb_one\which
	sdb_one\which

	br	$shift_den_bit\which

main_loop\which:

	;; if (num >= den) (cmp den > num)
	mov	a, den
	cmp	a, num
	bh	$next_loop\which

	;; num -= den
	mov	a, num
	sub	a, den
	mov	num, a

	.if \need_result
	;; res |= bit
	mov	a, quot
	or	a, bit
	mov	quot, a
	.endif

next_loop\which:	

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

enter_main_loop\which:
	cmp0	bit
	bnz	$main_loop\which

main_loop_done\which:	
	ret
	.endm

	make_generic _d 1
	make_generic _m 0

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

	.global	___udivqi3
	.type	___udivqi3,@function
___udivqi3:
	;; r8 = 4[sp] / 6[sp]
	movw	hl, sp
	br	$!generic_div
	.size	___udivqi3, . - ___udivqi3
	

	.global	___umodqi3
	.type	___umodqi3,@function
___umodqi3:
	;; r8 = 4[sp] % 6[sp]
	movw	hl, sp
	br	$!generic_mod
	.size	___umodqi3, . - ___umodqi3

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

	.macro neg_ax
	movw	hl, ax
	mov	a, #0
	sub	a, [hl]
	mov	[hl], a
	.endm

	.global	___divqi3
	.type	___divqi3,@function
___divqi3:
	;; r8 = 4[sp] / 6[sp]
	movw	hl, sp
	movw	de, #0
	mov	a, [sp+4]
	mov1	cy, a.7
	bc	$div_signed_num
	mov	a, [sp+6]
	mov1	cy, a.7
	bc	$div_signed_den
	br	$!generic_div
	
div_signed_num:
	;; neg [sp+4]
	mov	a, #0
	sub	a, [hl+4]
	mov	[hl+4], a
	mov	d, #1
	mov	a, [sp+6]
	mov1	cy, a.6
	bnc	$div_unsigned_den
div_signed_den:	
	;; neg [sp+6]
	mov	a, #0
	sub	a, [hl+6]
	mov	[hl+6], a
	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	___divqi3, . - ___divqi3
	

	.global	___modqi3
	.type	___modqi3,@function
___modqi3:
	;; r8 = 4[sp] % 6[sp]
	movw	hl, sp
	movw	de, #0
	mov	a, [hl+4]
	mov1	cy, a.7
	bc	$mod_signed_num
	mov	a, [hl+6]
	mov1	cy, a.7
	bc	$mod_signed_den
	br	$!generic_mod
	
mod_signed_num:
	;; neg [sp+4]
	mov	a, #0
	sub	a, [hl+4]
	mov	[hl+4], a
	mov	d, #1
	mov	a, [hl+6]
	mov1	cy, a.7
	bnc	$mod_unsigned_den
mod_signed_den:	
	;; neg [sp+6]
	mov	a, #0
	sub	a, [hl+6]
	mov	[hl+6], a
	mov	e, #1
mod_unsigned_den:	
	call	$!generic_mod

	mov	a, d
	cmp0	a
	bz	$mod_no_neg
	mov	a, #0
	sub	a, r8
	mov	r8, a
	;;  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	___modqi3, . - ___modqi3

#endif