1/* urem.s 6.2 84/08/01 2 * 3 * urem - unsigned remainder for vax-11 4 * 5 * arguments: dividend, divisor 6 * result: remainder 7 * uses r0-r2 8 * 9 * if 1 < divisor <= 2147483647, zero-extend the dividend 10 * to 64 bits and let ediv do the work. If the divisor is 1, 11 * ediv will overflow if bit 31 of the dividend is on, so 12 * just return 0. If the divisor is 0, do the ediv also, 13 * so it will generate the proper exception. All other values 14 * of the divisor have bit 31 on: in this case the remainder 15 * must be the dividend if divisor > dividend, and the dividend 16 * minus the divisor otherwise. The comparison must be unsigned. 17 */ 18 .text 19 .align 1 20 .globl urem 21urem: .word 0x0000 22#ifdef GPROF 23 jsb mcount 24#endif GPROF 25 movl 4(ap),r0 # Dividend 26 movl 8(ap),r2 # Divisor 27 jeql div # If divisor=0, force exception 28 cmpl r2,$1 # If divisor <= 1 (signed), 29 jleq nodiv # no division is necessary 30div: clrl r1 # Zero-extend the dividend 31 ediv r2,r0,r2,r0 # Divide. q->r2 (discarded), r->r0 32 ret 33nodiv: jneq nzero # If divisor=1, return 0 34 clrl r0 # (because doing the divide will overflow 35 ret # if the dividend has its high bit on) 36nzero: cmpl r0,r2 # If dividend < divisor (unsigned) 37 jlssu retn # remainder is dividend 38 subl2 r2,r0 # else remainder is dividend - divisor 39retn: ret 40