1# udiv.s 5.1 82/07/15 2# 3# udiv - unsigned division for vax-11 4# 5# arguments: dividend, divisor. 6# result: quotient. 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 the dividend unchanged. If the divisor is 0, 13# do the ediv also, so it will generate the proper exception. 14# All other values of the divisor have bit 31 on: in this case 15# the quotient must be 0 if divisor > dividend, and 1 otherwise, 16# provided that the comparison is made as unsigned. 17# 18 .text 19 .align 1 20 .globl udiv 21udiv: .word 0x0000 22 movl 4(ap),r0 # Dividend 23 movl 8(ap),r2 # Divisor 24 jeql div # If divisor=0, force exception 25 cmpl r2,$1 # If divisor <= 1 (signed), 26 jleq nodiv # no division is necessary 27div: clrl r1 # Zero-extend the dividend 28 ediv r2,r0,r0,r2 # Divide. q->r0, r->r2 (discarded) 29 ret 30nodiv: jeql retn # If divisor=1, return dividend 31 cmpl r0,r2 # Unsigned comparison between 32 jgequ one # dividend and divisor 33 clrl r0 # Dividend < divisor, return 0 34 ret 35one: movl $1,r0 # Dividend >= divisor, return 1 36retn: ret 37 38 39