Dis-assembly of NASCOM ROM BASIC Ver 4.7 PAGE 94
FCC8 CD39FE CASFFW: CALL FLPLED ; Turn on cassette
FCCB 0600 LD B,0 ; Set 1 second delay
FCCD CD9BFD DELAYB: CALL DELAY ; Wait a bit
FCD0 05 DEC B ; Count
FCD1 C2CDFC JP NZ,DELAYB ; More delay needed
FCD4 C9 RET
FCD5 C339FE CASFF: JP FLPLED ; Flip tape LED
FCD8 C9 ARET: RET ; A RETurn instruction
FCD9 E5 CONMON: PUSH HL ; Output character to screen
FCDA C5 PUSH BC ;
FCDB D5 PUSH DE ;
FCDC F5 PUSH AF ;
FCDD CD6DFE CALL MONTST ; See if NAS-SYS
FCE0 C2FBFC JP NZ,NASOUT ; NAS-SYS - Output ASCII
FCE3 F1 POP AF ; Get character
FCE4 F5 PUSH AF ; And re-save
FCE5 FE0A CP LF ; ASCII Line feed?
FCE7 CA00FD JP Z,IGCHR ; Yes - Ignore it
FCEA FE08 CP BKSP ; ASCII back space?
FCEC C2F1FC JP NZ,CONOT1 ; No - Test for CR
FCEF 3E1D LD A,TBS ; NASBUG back space
FCF1 FE0D CONOT1: CP CR ; ASCII CR?
FCF3 C2FDFC JP NZ,OUTCHR ; No - Output character
FCF6 3E1F LD A,TCR ; NASBUG CR
FCF8 C3FDFC JP OUTCHR ; Output it
FCFB F1 NASOUT: POP AF ; Get character
FCFC F5 PUSH AF ; And re-save
FCFD CD45FE OUTCHR: CALL MONOUT ; Output it
FD00 F1 IGCHR: POP AF ; Restore character
FD01 D1 POP DE ;
FD02 C1 POP BC ;
FD03 E1 POP HL ;
FD04 C9 RET
FD05 E5 GETINP: PUSH HL ; Get an input character
FD06 C5 PUSH BC ;
FD07 D5 PUSH DE ;
FD08 CD6DFE CALL MONTST ; See if NAS-SYS
FD0B CA13FD JP Z,GETTIN ; "T" monitor - Get input
FD0E DF0B SCAL BLINK
FD10 C319FD JP CONVIN ; Convert to ASCII
FD13 CD4D0C GETTIN: CALL TIN ; "T" input a character
FD16 D213FD JP NC,GETTIN ; No input - wait
FD19 FE1D CONVIN: CP TBS ; NASBUG back space?
FD1B C220FD JP NZ,CNVIN1 ; No - Test for break
FD1E 3E08 LD A,BKSP ; ASCII back space
FD20 FE1C CNVIN1: CP TBRK ; NASBUG break?
FD22 C227FD JP NZ,CNVIN2 ; No - Test for control Z
FD25 3E03 LD A,CTRLC ; Control C
FD27 FE1A CNVIN2: CP CTRLZ ; ^Z?
FD29 C22EFD JP NZ,CNVIN3 ; No - Test for escape
FD2C 3E7F LD A,DEL ; Delete
FD2E FE1B CNVIN3: CP ESC ; "ESC" ?
FD30 C235FD JP NZ,CNVIN4 ; No - Test for CR
FD33 3E03 LD A,CTRLC ; Control C
FD35 FE1F CNVIN4: CP TCR ; NASBUG CR?
FD37 C23CFD JP NZ,CNVIN5 ; No - Return character
FD3A 3E0D LD A,CR ; ASCII CR
FD3C D1 CNVIN5: POP DE
FD3D C1 POP BC
FD3E E1 POP HL
FD3F C9 RET
Dis-assembly of NASCOM ROM BASIC Ver 4.7 PAGE 95
FD40 AF CHKBRK: XOR A ; Check for break
FD41 CD70FD CALL SFTENT ; Test for shift/enter
FD44 CA50FD JP Z,TBRK2 ; Yes - Test for second break
FD47 3A4D10 LD A,(BRKFLG) ; Get break flag
FD4A B7 OR A ; Break flag set?
FD4B C250FD JP NZ,TBRK2 ; Yes - Test for second break
FD4E AF XOR A ; Flag no break
FD4F C9 RET
FD50 CD53FE TBRK2: CALL BREAK2 ; Second break?
FD53 3EFF LD A,-1 ; Flag break
FD55 C9 RET
FD56 DB02 GUART: IN A,(UARTS) ; Get UART status
FD58 17 RLA ; Any data ready?
FD59 D256FD JP NC,GUART ; No - wait until there is
FD5C DB01 IN A,(UARTD) ; Get data from UART
FD5E C9 RET
FD5F D301 UARTOT: OUT (UARTD),A ; Send data to UART
FD61 DB02 URTOLP: IN A,(UARTS) ; Get status
FD63 87 ADD A,A ; Byte sent?
FD64 F8 RET M ; Yes - Return
FD65 C361FD JP URTOLP ; Keep waiting
FD68 F5 SUART: PUSH AF ; Save A
FD69 CD5FFD CALL UARTOT ; Send it to UART
FD6C F1 POP AF ; Restore A
FD6D C9 RET
FD6E 00 NOP
FD6F 00 NOP
FD70 E5 SFTENT: PUSH HL ; Test for Shift Enter from KBD
FD71 3E02 LD A,00000010B ; Reset KBD counter mask
FD73 21000C LD HL,PORT0 ; Get old contents
FD76 AE XOR (HL) ; Toggle bit
FD77 D300 OUT (0),A ; Reset KBD counter
FD79 EE01 XOR 00000001B ; Toggle bit
FD7B D300 OUT (0),A ; Next row
FD7D EE02 XOR 00000010B
FD7F D300 OUT (0),A ; Clear "clear" strobe
FD81 7E LD A,(HL) ; Get old value
FD82 D300 OUT (0),A ; Original contents
FD84 19 ADD HL,DE ; ?? WHAT ??
FD85 E1 POP HL ; Restore HL
FD86 DB00 IN A,(0) ; Read in row
FD88 E612 AND 00010010B ; Mask SHIFT and ENTER
FD8A C9 RET
FD8B CD6DFE CLS: CALL MONTST ; See if NAS-SYS
FD8E CA96FD JP Z,TCLS ; "T" CLS
FD91 3E0C LD A,CS ; ASCII Clear screen
FD93 C3D9FC JP CONMON ; Output character
FD96 3E1E TCLS: LD A,TCS ; NASBUG Clear screen
FD98 C3D9FC JP CONMON ; Output character