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Entry points and work area 
IN WORK ( of the S-Basic MZ-2Z046 )  
General

The interpreter is loaded first to $1200 and next down by the monitor program from $1200 to commence at $0000.

The jump table at the start of the RAM Monitor has different addresses to the ROM Monitor ( see subroutines and workarea of the ROM Monitor 1Z-013A ), they are listed below, all addresses are in hex. Some appear to be unused while others are duplicated.

The tables show only a short description this time.
The information about the entry points of the interpreter's commands is listed only here.

The list of RAM Monitor and S-BASIC entry points and work area addresses is not a complete list, but it might assist those of you who are delving into the interpreter with your disassembler.

S-BASIC entry points / work area
Address
Description
$0000
 Cold start monitor / BASIC
$0003
Get line to workarea addressed by DE ( unused, all calls to $004A )
$0006
New line
$0009
 New line if the cursor isn't positioned at line begin
$000C
 Print space
$000F
Print tab. Sets the cursor to the next tab position
$0012
 Print character stored in Accu
$0015
Print message pointed to by DE ( unused, all calls to $0051 )
$0018
Execute software command
$001B check if key is pressed
$001E check if SHIFT-BREAK is pressed
$0021
 Write info header to tape ($3ADD = RET!)
$0024
Write data to tape ($3ADD = RET!)
$0027
 Read info header from tape ($3ADD = RET!)
$002A
 Read data from tape ($3ADD = RET!)
$002D
 Verify tape and program in RAM ($3ADD = RET!)
$0030
 $00B2 = RET
$0033
 Time set
$0038
 $00B2 = RET
$003B
 Read time
$003E
 Bell
$0041
 Set tempo
$0044
 Melody stop
$0047
 Melody stop
$004A
 Get line from keyboard
$004D = $5800 Address of cold start Basic Interpreter
$004F addresses of error routines
$0058 keyboard request / get key
$005B

Control code address table. Contains the address to jump to after the "PRINT CHR$"-statement or a key with the CTRL-key down ( The "NOACT" shown there means it will effect in an immediate return ).

Address CTRL & Action
$00B2 @ NOACT
$00B2 A NOACT (free for turn to ASCII keyboard)
$00B2 B NOACT (free for switching the border color)
$09B0 C CR
$00B2 D NOACT (free for turn to German keyboard)
$0A1B E Shift Lock
$0A19 F Alpha mode
$00B2 G plotter new color
$00B2 H NOACT (free for switching the background color)
$A024 I TAB
$00B2 J NOACT
$00B2 K NOACT (free for hardcopy)
$00B2 L NOACT
$09B0 M CR
$1500 N stop / start print
$00B2 O NOACT
$06BE P DEL
$09CF Q Cursor down
$09F9 R Cursor up
$09D4 S Cursor right
$09FE T Cursor left
$0992 U HOME
$061D V CLR
$0A1E W Graphic mode
$0776 X INS
$0A19 Y Alpha mode
$00B2 Z NOACT (free for switching the character color)
$09B0 Ä CR
$00B2 Ü NOACT
$00B2 Ö NOACT
$00B2 ^ NOACT
$00B2 / NOACT

$009B CTRL routine
$00A8 disable interrupts
$00B3 enable interrupts
$00BA PUSH IX, HL, BC, DE, AF
$00C7 PUSH IX, HL, BC, DE
$00D3 POP AF, DE, BC, HL, IX
$00DA switch from monitor to RAM $E000 - $FFFF
$00E6 break without message, no CONT possible
$00E8 BREAK
$00ED handle errors, Accu contains error number
$00F6 compute length of text (DE), end = $00
$0104 output table (HL) to port (C) in the length of B
$010D compute ASCII value (HL) to hex DE. Check upper limit in B.
$011B Compare the bytes behind the CALL instruction with the contents of the Accu in the length of B
$012D Pick up an address from table (HL) to DE. HL = HL + 1
$0132 Pick up an address from table (HL) to DE. HL = HL
$0137 Clear memory (HL) with $00 in the length of B
$0138 Fill memory (HL) with the value in the accu in the length of B
$013D Clear memory (DE) with $00 in the length of B
$0143 Move memory from (HL) to (DE) in the length of B
$014A Move memory from (DE) to (HL) in the length of B
$0151 Pick up an address from table (HL) to HL.
$0158 HL = HL + A
$015D skip spaces
$0164 Compare the byte behind the CALL instruction with the contents of (HL)
$016E like $0164, but if not then error 1
$017C table of software commands
$022C execute software command
$0247 CALL (IX) and display error if any
$025E Compute hex value in HL to ASCII value (DE)
$029E Compute decimal or hex ASCII (HL) to hex DE
$02CE Compute hex ASCII (HL) to hex DE
$02E9 Compute hex ASCII A to hex
$02F8 Wait on space key then next key
$0305 Wait on any key. If BRK key then break program execution
$0314 Store device table pointer DE and device number A
$031C Correct pointer to the I/O workarea, basic variables area, and strings area
$0323 Correct pointer to the basic variables area and strings area
$032A Correct pointer to the strings area
$0340 Print error. A contains error number
$0397 Move the actual device name to (HL)
$03B6 Text "error"
$03BE Set screen mode
$0419 Init palette register and set maximum of the scroll area
$0441 Init palette register and init base colors black/blue/red/white
$044F Set palette block number
$0476 Color code to palette register (B = color code, A = palette code number)
$048A Set character color to palette value in A
$0493 Set graphic color to palette value in A
$049C Correct the palette value in A for the max. resolution
$04AE Compute the values of start / end scroll coordinates then output these to the controller.
$04EF Set screen routines to 40 or 80 columns
$0531 Init routines using values from (HL)
$054F

Table values for setting to 40 or 80 columns
$05AD Print accu
$05CE Print accu on graphic screen
$05F9 Compute Y coordinates to DE
$0615 Get pointer to Y coordinate to HL
$061D CLR
$0671 Clear memory area
$06AC Reset scroll offset
$06BE DEL
$0776 INST
$0848 Scroll
$08E5 Change character at cursor position for flashing cursor
$092B Init keyboard and show cursor
$0945 Show cursor or character
$094D New cursor position by HL
$0963 Compute text cursor position in pseudo screen by coordinates from HL
$0977 Compute the graphic screen address by the actual cursor position
$0992 HOME
$099B New line, if the cursor position > 0
$09AB New line
$09CF Cursor down
$09D4 Cursor right
$09E3 Concatenate lines and scroll conditional
$09F9 Cursor up
$09FE Cursor left
$0A19 ALPHA
$0A1B SMALL
$0A1E GRAPH
$0A24 TAB
$0A24 Get line form keyboard to memory (DE)
$0AB4 BRK-key
$0ABB Fetch textline from screen into the input area
$0BA1 Check for kbd input. Statuscode returns in A.
$0B7B Check for kbd input again.
$0B8B Check for kbd input without rebounce.
$0BA1 Check for kbd input. Keycode returns in A
$0BAB Check if a function key is pressed. Get a character.
$0BC1 Check if kbd input has changed
$0BF6 Check for kbd input; returns ASCII
$0C75 Check if function key is used.
$0CAB Compute to ASCII key code
$0CEF Identify CTRL-key
$0D22 Check for BRK condition (SHIFT/BRK)
$0D30 KEY work area
$0D47 Key codes translation table
$0D8F CTRL keys translation table
$0D94 Print text (DE) depending on a Ctrl-code for upper-/lowercase output.
$0DC3 SHARP ASCII table of lowercase letters
$0DDD CRT-device table
$0DF6 KEY device table
$0E0F Get kbd line and compute line length
$0E17 character in A
$0E26 get current screen X-value
$0E2A new line or CRT/LPT
$0E2C Print A to CRT/LPT. Ctrl codes will be executed.
$0E3A Print A to CRT/LPT. Ctrl codes will be displayed.
$0E48 Print text (DE) to CRT/LPT
$0E50 Print text (DE) to CRT. Ctrl codes will be executed.
$0E5F Print space to CRT
$0E61 Print A to CRT. Ctrl codes will be executed.
$0EA2 Print A to CRT. Ctrl codes will be displayed.
$0ED9 Ctrl code translation table for LPT output
$0EF9 Boot routine used by the Monitor/Basic
$0F2D identify the load device and set it to the actual device
$0F4E Check for graphic expansion option
$0F7F device table for USR routines
$0F98 prepare addresses for USR routines
$0FA7 USR device data I/O
$0FFC Music interrupt address
$0FFE Printer interrupt address
$1000 workarea for file attributes
$104A workarea for current device table
$1069 workarea for default device data
$1070 pointer workarea
$1082 cursor workarea
$11A4 workarea / inputarea
$12B2 text area of function keys
$1352 area for values of the current function key
$1369 current screen values


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last updated January 15, 2004
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