xref: /kernel/linux/linux-5.10/arch/h8300/lib/udivsi3.S (revision 8c2ecf20)
18c2ecf20Sopenharmony_ci/* SPDX-License-Identifier: GPL-2.0 */
28c2ecf20Sopenharmony_ci#include "libgcc.h"
38c2ecf20Sopenharmony_ci
48c2ecf20Sopenharmony_ci	;; This function also computes the remainder and stores it in er3.
58c2ecf20Sopenharmony_ci	.global	__udivsi3
68c2ecf20Sopenharmony_ci__udivsi3:
78c2ecf20Sopenharmony_ci	mov.w	A1E,A1E		; denominator top word 0?
88c2ecf20Sopenharmony_ci	bne	DenHighNonZero
98c2ecf20Sopenharmony_ci
108c2ecf20Sopenharmony_ci	; do it the easy way, see page 107 in manual
118c2ecf20Sopenharmony_ci	mov.w	A0E,A2
128c2ecf20Sopenharmony_ci	extu.l	A2P
138c2ecf20Sopenharmony_ci	divxu.w	A1,A2P
148c2ecf20Sopenharmony_ci	mov.w	A2E,A0E
158c2ecf20Sopenharmony_ci	divxu.w	A1,A0P
168c2ecf20Sopenharmony_ci	mov.w	A0E,A3
178c2ecf20Sopenharmony_ci	mov.w	A2,A0E
188c2ecf20Sopenharmony_ci	extu.l	A3P
198c2ecf20Sopenharmony_ci	rts
208c2ecf20Sopenharmony_ci
218c2ecf20Sopenharmony_ci	; er0 = er0 / er1
228c2ecf20Sopenharmony_ci	; er3 = er0 % er1
238c2ecf20Sopenharmony_ci	; trashes er1 er2
248c2ecf20Sopenharmony_ci	; expects er1 >= 2^16
258c2ecf20Sopenharmony_ciDenHighNonZero:
268c2ecf20Sopenharmony_ci	mov.l	er0,er3
278c2ecf20Sopenharmony_ci	mov.l	er1,er2
288c2ecf20Sopenharmony_ci#ifdef CONFIG_CPU_H8300H
298c2ecf20Sopenharmony_cidivmod_L21:
308c2ecf20Sopenharmony_ci	shlr.l	er0
318c2ecf20Sopenharmony_ci	shlr.l	er2		; make divisor < 2^16
328c2ecf20Sopenharmony_ci	mov.w	e2,e2
338c2ecf20Sopenharmony_ci	bne	divmod_L21
348c2ecf20Sopenharmony_ci#else
358c2ecf20Sopenharmony_ci	shlr.l	#2,er2		; make divisor < 2^16
368c2ecf20Sopenharmony_ci	mov.w	e2,e2
378c2ecf20Sopenharmony_ci	beq	divmod_L22A
388c2ecf20Sopenharmony_cidivmod_L21:
398c2ecf20Sopenharmony_ci	shlr.l	#2,er0
408c2ecf20Sopenharmony_cidivmod_L22:
418c2ecf20Sopenharmony_ci	shlr.l	#2,er2		; make divisor < 2^16
428c2ecf20Sopenharmony_ci	mov.w	e2,e2
438c2ecf20Sopenharmony_ci	bne	divmod_L21
448c2ecf20Sopenharmony_cidivmod_L22A:
458c2ecf20Sopenharmony_ci	rotxl.w	r2
468c2ecf20Sopenharmony_ci	bcs	divmod_L23
478c2ecf20Sopenharmony_ci	shlr.l	er0
488c2ecf20Sopenharmony_ci	bra	divmod_L24
498c2ecf20Sopenharmony_cidivmod_L23:
508c2ecf20Sopenharmony_ci	rotxr.w	r2
518c2ecf20Sopenharmony_ci	shlr.l	#2,er0
528c2ecf20Sopenharmony_cidivmod_L24:
538c2ecf20Sopenharmony_ci#endif
548c2ecf20Sopenharmony_ci	;; At this point,
558c2ecf20Sopenharmony_ci	;;  er0 contains shifted dividend
568c2ecf20Sopenharmony_ci	;;  er1 contains divisor
578c2ecf20Sopenharmony_ci	;;  er2 contains shifted divisor
588c2ecf20Sopenharmony_ci	;;  er3 contains dividend, later remainder
598c2ecf20Sopenharmony_ci	divxu.w	r2,er0		; r0 now contains the approximate quotient (AQ)
608c2ecf20Sopenharmony_ci	extu.l	er0
618c2ecf20Sopenharmony_ci	beq	divmod_L25
628c2ecf20Sopenharmony_ci	subs	#1,er0		; er0 = AQ - 1
638c2ecf20Sopenharmony_ci	mov.w	e1,r2
648c2ecf20Sopenharmony_ci	mulxu.w	r0,er2		; er2 = upper (AQ - 1) * divisor
658c2ecf20Sopenharmony_ci	sub.w	r2,e3		; dividend - 65536 * er2
668c2ecf20Sopenharmony_ci	mov.w	r1,r2
678c2ecf20Sopenharmony_ci	mulxu.w	r0,er2		; compute er3 = remainder (tentative)
688c2ecf20Sopenharmony_ci	sub.l	er2,er3		; er3 = dividend - (AQ - 1) * divisor
698c2ecf20Sopenharmony_cidivmod_L25:
708c2ecf20Sopenharmony_ci	cmp.l	er1,er3		; is divisor < remainder?
718c2ecf20Sopenharmony_ci	blo	divmod_L26
728c2ecf20Sopenharmony_ci	adds	#1,er0
738c2ecf20Sopenharmony_ci	sub.l	er1,er3		; correct the remainder
748c2ecf20Sopenharmony_cidivmod_L26:
758c2ecf20Sopenharmony_ci	rts
768c2ecf20Sopenharmony_ci
778c2ecf20Sopenharmony_ci	.end
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