path: root/libgcc/config/rl78/divmodsi.S

/* SImode 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 = r12
	den = r16
	bit = r20
	.else
	num = r8
	quot = r12
	den = r16
	bit = r20
	.endif

	quotH = quot+2
	quotL = quot
	quotB0 = quot
	quotB1 = quot+1
	quotB2 = quot+2
	quotB3 = quot+3
	
	numH = num+2
	numL = num
	numB0 = num
	numB1 = num+1
	numB2 = num+2
	numB3 = num+3
	
#define	denH bc
	denL = den
	denB0 = den
	denB1 = den+1
#define	denB2 c
#define	denB3 b
	
	bitH = bit+2
	bitL = bit
	bitB0 = bit
	bitB1 = bit+1
	bitB2 = bit+2
	bitB3 = bit+3

num_lt_den\which:
	.if \need_result
	movw	r8, #0
	movw	r10, #0
	.else
	movw	ax, [sp+8]
	movw	r8, ax
	movw	ax, [sp+10]
	movw	r10, ax
	.endif
	ret

shift_den_bit16\which:
	movw	ax, denL
	movw	denH, ax
	movw	denL, #0
	.if \need_result
	movw	ax, bitL
	movw	bitH, ax
	movw	bitL, #0
	.else
	mov	a, bit
	add	a, #16
	mov	bit, a
	.endif
	br	$shift_den_bit\which

	;; 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] /% 12[sp]

	movw	hl, sp
	movw	ax, [hl+14] ; denH
	cmpw	ax, [hl+10] ; numH
	movw	ax, [hl+12] ; denL
	sknz
	cmpw	ax, [hl+8] ; numL
	bh	$num_lt_den\which

	sel	rb2
	push	ax		; denL
;	push	bc		; denH
	push	de		; bitL
	push	hl		; bitH - stored in BC
	sel	rb0

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

	;; copy numerator
	movw	ax, [hl+8]
	movw	numL, ax
	movw	ax, [hl+10]
	movw	numH, ax

	;; copy denomonator
	movw	ax, [hl+12]
	movw	denL, ax
	movw	ax, [hl+14]
	movw	denH, ax

	movw	ax, denL
	or	a, denB2
	or	a, denB3	; not x
	cmpw	ax, #0
	bnz	$den_not_zero\which
	movw	numL, #0
	movw	numH, #0
	ret

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

	;; initialize bit to 1
	movw	bitL, #1
	movw	bitH, #0

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

	.if 1
	;; see if we can short-circuit a bunch of shifts
	movw	ax, denH
	cmpw	ax, #0
	bnz	$shift_den_bit\which
	movw	ax, denL
	cmpw	ax, numH
	bnh	$shift_den_bit16\which
	.endif

shift_den_bit\which:	
	movw	ax, denH
	mov1	cy,a.7
	bc	$enter_main_loop\which
	cmpw	ax, numH
	movw	ax, denL	; we re-use this below
	sknz
	cmpw	ax, numL
	bh	$enter_main_loop\which

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

	;; bit <<= 1
	.if \need_result
	movw	ax, bitL
	shlw	ax, 1
	movw	bitL, ax
	movw	ax, bitH
	rolwc	ax, 1
	movw	bitH, ax
	.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

	;; while (bit)
main_loop\which:

	;; if (num >= den) (cmp den > num)
	movw	ax, numH
	cmpw	ax, denH
	movw	ax, numL
	sknz
	cmpw	ax, denL
	skz
	bnh	$next_loop\which

	;; num -= den
;	movw	ax, numL	; already has it from the cmpw above
	subw	ax, denL
	movw	numL, ax
	movw	ax, numH
	sknc
	decw	ax
	subw	ax, denH
	movw	numH, ax

	.if \need_result
	;; res |= bit
	mov	a, quotB0
	or	a, bitB0
	mov	quotB0, a
	mov	a, quotB1
	or	a, bitB1
	mov	quotB1, a
	mov	a, quotB2
	or	a, bitB2
	mov	quotB2, a
	mov	a, quotB3
	or	a, bitB3
	mov	quotB3, a
	.endif

next_loop\which:	

	;; den >>= 1
	movw	ax, denH
	shrw	ax, 1
	movw	denH, ax
	mov	a, denB1
	rorc	a, 1
	mov	denB1, a
	mov	a, denB0
	rorc	a, 1
	mov	denB0, a

	;; bit >>= 1
	.if \need_result
	movw	ax, bitH
	shrw	ax, 1
	movw	bitH, ax
	mov	a, bitB1
	rorc	a, 1
	mov	bitB1, a
	mov	a, bitB0
	rorc	a, 1
	mov	bitB0, a
	.else
	dec	bitB0
	.endif

enter_main_loop\which:
	.if \need_result
	movw	ax, bitH
	cmpw	ax, #0
	bnz	$main_loop\which
	.else
	cmp	bitB0, #15
	bh	$main_loop\which
	.endif
	;; bit is HImode now; check others
	movw	ax, numH	; numerator
	cmpw	ax, #0
	bnz	$bit_high_set\which
	movw	ax, denH	; denominator
	cmpw	ax, #0
	bz	$switch_to_himode\which
bit_high_set\which:	
	.if \need_result
	movw	ax, bitL
	cmpw	ax, #0
	.else
	cmp0	bitB0
	.endif
	bnz	$main_loop\which

switch_to_himode\which:
	.if \need_result
	movw	ax, bitL
	cmpw	ax, #0
	.else
	cmp0	bitB0
	.endif
	bz	$main_loop_done_himode\which

	;; From here on in, r22, r14, and r18 are all zero
	;; while (bit)
main_loop_himode\which:

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

	;; num -= den
	movw	ax, numL
	subw	ax, denL
	movw	numL, ax
	movw	ax, numH
	sknc
	decw	ax
	subw	ax, denH
	movw	numH, 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_himode\which:	

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

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

	.if \need_result
	movw	ax, bitL
	cmpw	ax, #0
	.else
	cmp0	bitB0
	.endif
	bnz	$main_loop_himode\which

main_loop_done_himode\which:	
	sel	rb2
	pop	hl		; bitH - stored in BC
	pop	de		; bitL
;	pop	bc		; denH
	pop	ax		; denL
	sel	rb0

	ret
	.endm

	make_generic _d 1
	make_generic _m 0

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

	.global	___udivsi3
	.type	___udivsi3,@function
___udivsi3:
	;; r8 = 4[sp] / 8[sp]
	call	$!generic_div
	ret
	.size	___udivsi3, . - ___udivsi3
	

	.global	___umodsi3
	.type	___umodsi3,@function
___umodsi3:
	;; r8 = 4[sp] % 8[sp]
	call	$!generic_mod
	ret
	.size	___umodsi3, . - ___umodsi3

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

	.macro neg_ax
	movw	hl, ax
	movw	ax, #0
	subw	ax, [hl]
	movw	[hl], ax
	movw	ax, #0
	sknc
	decw	ax
	subw	ax, [hl+2]
	movw	[hl+2], ax
	.endm

	.global	___divsi3
	.type	___divsi3,@function
___divsi3:
	;; r8 = 4[sp] / 8[sp]
	movw	de, #0
	mov	a, [sp+7]
	mov1	cy, a.7
	bc	$div_signed_num
	mov	a, [sp+11]
	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+11]
	mov1	cy, a.7
	bnc	$div_unsigned_den
div_signed_den:	
	;; neg [sp+8]
	movw	ax, sp
	addw	ax, #8
	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
	;;  We have to restore the denominator [sp+8]
	movw	ax, sp
	addw	ax, #8
	neg_ax
div_skip_restore_den:
	ret
	.size	___divsi3, . - ___divsi3
	

	.global	___modsi3
	.type	___modsi3,@function
___modsi3:
	;; r8 = 4[sp] % 8[sp]
	movw	de, #0
	mov	a, [sp+7]
	mov1	cy, a.7
	bc	$mod_signed_num
	mov	a, [sp+11]
	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+11]
	mov1	cy, a.7
	bnc	$mod_unsigned_den
mod_signed_den:	
	;; neg [sp+8]
	movw	ax, sp
	addw	ax, #8
	neg_ax
	mov	e, #1
mod_unsigned_den:	
	call	$!generic_mod

	mov	a, d
	cmp0	a
	bz	$mod_no_neg
	movw	ax, #r8
	neg_ax
	;;  We have to restore [sp+4] as well.
	movw	ax, sp
	addw	ax, #4
	neg_ax
mod_no_neg:
 .if 1
	mov	a, e
	cmp0	a
	bz	$mod_skip_restore_den
	movw	ax, sp
	addw	ax, #8
	neg_ax
mod_skip_restore_den:	
 .endif	
	ret
	.size	___modsi3, . - ___modsi3

#endif