; ; Test of alleged bug in DCON and DDT ; where JZ and JNZ supposedly trace ; incorrectly. Result: no bug found. ; 05/28/82 and 05/29/82 (Ron Fowler) ; | | ; | | ; | ---> lowercase ; --------------> uppercase ; ORG 100H ; ; ; TEST | RESULT ; ---- | ------ ; | LOOP: ORI 1 ;RESET Z | JNZ NOZ1 ;TEST JNZ--------->| went to noz1, as expected JZ YESZ1 ;TEST JZ---------->| never got here ; | ; CAN'T GET HERE FROM UP THERE | ; (from noz1 or yesz1 only) | ; | STEP2: XRA A ;SET Z | JNZ NOZ2 ;TEST JNZ--------->| didn't jump, as expected JZ YESZ2 ;----------------->| went to yesz2, expected ; | ; CAN'T GET HERE FROM UP THERE | ; | step3: mvi b,8 ;do a subtraction | mvi a,8 ;that =0 | sub b ; | jnz noz3 ;----------------->| didn't jump here, expected jz yesz3 ;----------------->| jumped here as expected ; | ; ditto here from there | ; | step4: mvi b,8 ;do subtraction | mvi a,9 ; that's nz | sub b ; | jnz noz4 ;----------------->| jumped here, as expected jz yesz4 ;----------------->| never got here, expected ; ; can't be here ; jmp loop ;but do something anyway ; ; Turnaround here, and proceed to next step ; NOZ1: JMP STEP2 YESZ1: JMP STEP2 ; NOZ2: JMP step3 ;new further testing YESZ2: JMP step3 ; noz3: jmp step4 ;one more test yesz3: jmp step4 ; noz4: jmp loop ;repeat entire test yesz4: jmp loop ; end