;
-; Zeropage and I/O definitions for the CBM 610
+; Zero page variables and I/O definitions for the CBM 610
;
; Taken from a kernal disassembly done by myself in 1987.
;
-; Ullrich von Bassewitz, 28.09.1998
+; 1998-09-28, Ullrich von Bassewitz
+; 2014-04-02, Greg King
; ---------------------------------------------------------------------------
-; Zeropage registers
+; Zeropage stuff
-ExecReg = $00
-IndReg = $01
+ExecReg := $00 ; Controls execution memory bank
+IndReg := $01 ; Controls indirect indexed load-store bank
+
+TXTPTR := $85 ; Far pointer into BASIC source code
+FNAM := $90 ; Far pointer to LOAD/SAVE file-name
+FNAM_LEN := $9D ; Holds length of file-name
; ---------------------------------------------------------------------------
; Screen size
; I/O $d800: CRTC 6545
.struct CRTC
- ADDR .byte
- DATA .byte
+ ADDR .byte
+ DATA .byte
.endstruct
-; I/O $db00: CIA 6526 Inter Process Communication
+
+; I/O $db00: CIA 6526, Inter Process Communication
;
-; IPCcia = $db00
+; IPCcia = $db00
.struct CIA
PRA .byte
; I/O $dc00: CIA 6526
;
-; cia = $dc00
-
+; cia = $dc00
; I/O $dd00: ACIA 6551
;
-; acia = $dd00
+; acia = $dd00
.struct ACIA
DATA .byte
; I/O $de00: Triport #1 6525
;
-; tpi1 = $de00
+; tpi1 = $de00
.struct TPI
PRA .byte
; I/O $df00: Triport #2 6525
-; tpi2 = $df00
+; tpi2 = $df00
+
+;-----------------------------------------------------------------------------
+BASIC_BUF := $FA5E ; Bank 1 location of command-line
+BASIC_BUF_LEN = 162 ; Maximum length of command-line