1/* 2 * @(#)urem.s 6.3 (Berkeley) 06/08/85 3 * 4 * urem - unsigned remainder for vax-11 5 * 6 * arguments: dividend, divisor 7 * result: remainder 8 * uses r0-r2 9 * 10 * if 1 < divisor <= 2147483647, zero-extend the dividend 11 * to 64 bits and let ediv do the work. If the divisor is 1, 12 * ediv will overflow if bit 31 of the dividend is on, so 13 * just return 0. If the divisor is 0, do the ediv also, 14 * so it will generate the proper exception. All other values 15 * of the divisor have bit 31 on: in this case the remainder 16 * must be the dividend if divisor > dividend, and the dividend 17 * minus the divisor otherwise. The comparison must be unsigned. 18 */ 19 .text 20 .align 1 21 .globl urem 22urem: .word 0x0000 23#ifdef GPROF 24 jsb mcount 25#endif GPROF 26 movl 4(ap),r0 # Dividend 27 movl 8(ap),r2 # Divisor 28 jeql div # If divisor=0, force exception 29 cmpl r2,$1 # If divisor <= 1 (signed), 30 jleq nodiv # no division is necessary 31div: clrl r1 # Zero-extend the dividend 32 ediv r2,r0,r2,r0 # Divide. q->r2 (discarded), r->r0 33 ret 34nodiv: jneq nzero # If divisor=1, return 0 35 clrl r0 # (because doing the divide will overflow 36 ret # if the dividend has its high bit on) 37nzero: cmpl r0,r2 # If dividend < divisor (unsigned) 38 jlssu retn # remainder is dividend 39 subl2 r2,r0 # else remainder is dividend - divisor 40retn: ret 41