;; This example shows how to read a sector from ;; a DATA format disc ;; ;; This code is public domain and can be used in your ;; own programs. ;; ;; Written by Kevin Thacker, 2002. ;; ;;------------------------------------------------ ;; firmware function to find a RSX .kl_find_command equ &bcd4 org &8000 nolist ;;------------------------------------------------ ;; find BIOS: READ SECTOR command ;; ;; This method is compatible with other DOSs that ;; override or provide this command. If the command ;; is not found, then there is no furthur action. Therefore ;; on tape based systems, this code will have no effect. ld hl,cmd_bios_read_sector call kl_find_command ret nc ;; command found ;; store address of command ld (bios_read_sector),hl ;; store "rom select" of command ld a,c ld (bios_read_sector+2),a ;;------------------------------------------------------------------ ;; read 512 bytes of data from track 0, sector &C1 from disc drive 0 ;; HL = address of buffer ;; (change this value to define a different buffer address) ld hl,buffer ;; E = drive number (0 or 1) ;; (change this value to define the disc drive to read from) ld e,0 ;; D = track number ;; (change this value to define the track to read from) ld d,0 ;; C = sector id ;; ;; sector ids for DATA format disc: &C1, &C2, &C3, &C4, &C5, &C6, &C7, &C8, &C9 ;; sector ids for SYSTEM/VENDOR format disc: &41, &42, &43, &44, &45, &46, &47, &48, &49 ;; ;; (change this value to define the id of the sector to read from) ld c,&c1 ;; execute command rst 3 defw bios_read_sector ret ;;------------------------------------------------------------------ ;; this is initialised when the "BIOS: READ SECTOR" RSX has been found. .bios_read_sector defw 0 ;; address of function defb 0 ;; "rom select" for function .cmd_bios_read_sector defb 4+&80 ;; this is the "BIOS: READ SECTOR" RSX ;;------------------------------------------------------------------ .buffer defs 512