And sure enough MBASIC 1975...there it is.
;--------- ---- -- ---- ----- --- ---- ----- ;COPYRIGHT 1975 BY BILL GATES AND PAUL ALLEN ;--------- ---- -- ---- ----- --- ---- ----- ; ;ORIGINALLY WRITTEN ON THE PDP-10 FROM ;FEBRUARY 9 TO APRIL 9 1975 ; ;BILL GATES WROTE A LOT OF STUFF. ;PAUL ALLEN WROTE OTHER STUFF AND FAST CODE. ;MONTE DAVIDOFF WROTE THE MATH PACKAGE (F4I.MAC). ------------------------------------------------------------- ; ;GET THE VALTYP AND SET CONDITION CODES AS FOLLOWS: ;;CONDITION CODE TRUE SET FALSE SET ;;SIGN INT=2 STR,SNG,DBL ;;ZERO STR=3 INT,SNG,DBL ;;ODD PARITY SNG=4 INT,STR,DBL ;;NO CARRY DBL=10 INT,STR,SNG ;GETYPE: LDA VALTYP ;GET THE VALTYP ; CPI 10 ;SET CARRY CORRECTLY ; DCR A ;SET THE OTHER CONDITION CODES CORRECTLY ; DCR A ; WITHOUT AFFECTING CARRY ; DCR A ; RET * ;ALL DONE On Thursday, December 19, 2024, George Phillips <[email protected]> wrote: > Yes, feel free to repost. > > You may want to check if parity comes up elsewhere. Looking at the Model 1 > ROM I see two places where the code may have been changed for the Z-80. > Once in the handling of arithmetic operators (+,-,*,/) and another when > computing array lookup addresses. In both cases there is an "OR A" before > a > "JP PO,". I think in the original 8080 version those "OR A" would not have > been necessary. > > -- George > > > On 12/19/2024 4:57 AM, Stephen Adolph wrote: > >> Do you mind if I post your answer on the VCFED forum thread I started on >> this subject? >> >>
