1 /* SPDX-License-Identifier: GPL-2.0 */
14  *	__divqu: 64-bit unsigned long divide
15  *	__remqu: 64-bit unsigned long remainder
16  *	__divqs/__remqs: signed 64-bit
17  *	__divlu/__remlu: unsigned 32-bit
18  *	__divls/__remls: signed 32-bit
27  * This is a rather simple bit-at-a-time algorithm: it's very good
28  * at dividing random 64-bit numbers, but the more usual case where
37  *	$0 - current bit
38  *	$1 - shifted divisor
39  *	$2 - modulus/quotient
41  *	$23 - return address
42  *	$24 - dividend
43  *	$25 - divisor
45  *	$27 - quotient/modulus
46  *	$28 - compare status
55 #define mask	$0  macro
62 #define DIV_ONLY(x,y...) x,##y  argument
63 #define MOD_ONLY(x,y...)  argument
64 #define func(x) __div##x  argument
67 #define GETSIGN(x) xor $24,$25,x  argument
70 #define DIV_ONLY(x,y...)  argument
71 #define MOD_ONLY(x,y...) x,##y  argument
72 #define func(x) __rem##x  argument
75 #define GETSIGN(x) bis $24,$24,x  argument
80  * For 32-bit operations, we need to extend to 64-bit
85 #define LONGIFY(x) zapnot x,15,x  argument
86 #define SLONGIFY(x) addl x,0,x  argument
90 #define LONGIFY(x)  argument
91 #define SLONGIFY(x)  argument
112 	bis	$31,1,mask
118 	 * shift divisor left, using 3-bit shifts for
119 	 * 32-bit divides as we can't overflow. Three-bit
127 	s8addq	mask,$31,mask
133 	addq	mask,mask,mask
139 2:	DIV_ONLY(addq quotient,mask,tmp2)
140 	srl	mask,1,mask
146 	bne	mask,2b
162  * 	-a / b = a / -b = -(a / b)
163  *	-a % b = -(a % b)
164  *	a % -b = a % b
166  * have the property that (x/y)*y + (x%y) = x.