.define .set .sect .text .sect .rom .sect .data .sect .bss .sect .text ! Create set with one bit on ! Expects in de-reg: size of set to be created ! Expects on stack: bit number ! Yields on stack: resulting set .set: pop h shld .retadr mov h,b mov l,c shld .bcreg mov a,e rar cc eoddz ! trap if size is odd xchg ! hl = size of set pop d ! de = bit number mov a,e ! c = bit number in byte ani 7 sta .areg ! save bit number in byte mvi b,3 ! de = byte number 1: xra a mov a,d rar mov d,a mov a,e rar mov e,a dcr b jnz 1b mov a,l ! trap if bit number is too large sub e mov a,h sbb d cc eset lxi b,0 ! make empty set on stack 1: push b dcx h dcx h mov a,l ora h jnz 1b lxi h,0 dad sp dad d ! hl points to byte that will contain a one lda .areg mov c,a ! c = bit number in byte mvi a,1 1: dcr c jm 2f rlc jmp 1b 2: mov m,a lhld .bcreg mov b,h mov c,l lhld .retadr pchl