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--- vc-3_system_interrupt_table [2026/02/02 08:25] – appledog
+++ vc-3_system_interrupt_table [Unknown date] (current) – removed - external edit (Unknown date) 127.0.0.1
@@ Line 1: / Line 1: @@
-= VC-3 System Interrupt Table
-The VC-3 is a system, running on the SD-8516.
-== Introduction
-I guess this interrupt system is part of the KERNAL, so should be more "VC-3" as it is system software. What follows is a simple list of the interrupt, what it does, it's calling parameters and it's return codes. I guess this should be called "Stellar BIOS V1" or "VC-3 KERNAL ROM" could be a nice name.
-== Calling Convention
-Each INT subsystem has it's own convention. However, the INT 05h system was done first so it represents a general convention you can expect going forward.
-=== Parameters
-* Function number: AH
-* Small values such as char can go in AL. Otherwise, inputs can go in B.
-* Pointers: ELM, ELD
-=== Returns
-* Values: B, and C if needed
-* Status: Carry flag
-* Pointers: ELM, ELD (see calling convention)
-=== Example Code
-<codify armasm>
-LDAL #'A'
-LDB #1234
-LDAH $11        ; VAR_SET
-INT $05
-LDELD @string
-LDAH $62        ; IO_GETNUM
-INT $05
-; B has parsed number
-</codify>
-== INT 05h - Pao Alto Tiny Basic
-=== Memory Map
-    ; PATB System Memory ($01ED00-$01EDFF, 256 bytes available)
-    .equ PATB_VARIABLES     $01ED00   ; 26 vars × 2 bytes = 52 bytes ($01ED00-$01ED33)
-    .equ PATB_EXPR_STACK    $01ED40   ; Expression stack, 64 bytes ($01ED40-$01ED7F)
-    .equ PATB_EXPR_SP       $01ED80   ; Expression stack pointer (2 bytes)
-    .equ PATB_GOSUB_STACK   $01ED82   ; GOSUB stack, 32 bytes (16 levels × 2 bytes)
-    .equ PATB_GOSUB_SP      $01EDA2   ; GOSUB stack pointer (2 bytes)
-    .equ PATB_FOR_STACK     $01EDA4   ; FOR stack, 40 bytes (8 levels × 5 bytes)
-    .equ PATB_FOR_SP        $01EDCC   ; FOR stack pointer (2 bytes)
-    .equ PATB_PROGRAM_PTR   $01EDCE   ; Current program line pointer (3 bytes)
-    .equ PATB_IL_PTR        $01EDD1   ; Current IL instruction pointer (3 bytes)
-    .equ PATB_INPUT_PTR     $01EDD4   ; Current input pointer (3 bytes)
-    .equ PATB_RANDSEED      $01EDD7   ; Random seed (2 bytes)
-    .equ PATB_STATUS        $01EDD9   ; Status flags (1 byte)
-                                      ; Bit 0: Running (1) / Stopped (0)
-                                      ; Bit 1: Error flag
-                                      ; Bit 2: Break flag
-    .equ PATB_PROGRAM_BASE  $030100   ; Start of program storage (Bank 3, offset $100)
-    .equ PATB_PROGRAM_END   $03FFFF   ; End (almost 64KB for programs)
-=== Function Dispatch
-    ; === EXECUTION CONTROL (AH=$00-$0F) ===
-    ;   AH=$00: RUN_PROGRAM    - Start execution from line number or beginning
-    ;   AH=$01: STOP_PROGRAM   - Stop execution
-    ;   AH=$02: CONTINUE       - Continue from current position
-    ;   AH=$03: EXEC_IL_STEP   - Execute one IL instruction
-    ;   AH=$04: EXEC_IL_CONT   - Execute IL until completion
-    ;   AH=$05: GET_STATUS     - Get interpreter status
-    ;   AH=$06: SET_STATUS     - Set interpreter status flags
-    ;   AH=$07: RESET_INTERP   - Reset interpreter state
-    ;
-    ; === VARIABLE MANAGEMENT (AH=$10-$1F) ===
-    ;   AH=$10: VAR_GET        - Get variable value by letter
-    ;   AH=$11: VAR_SET        - Set variable value by letter
-    ;   AH=$12: VAR_CLEAR_ALL  - Clear all variables to 0
-    ;   AH=$13: VAR_GET_ADDR   - Get address of variable storage
-    ;
-    ; === EXPRESSION STACK (AH=$20-$2F) ===
-    ;   AH=$20: EXPR_PUSH      - Push value to expression stack
-    ;   AH=$21: EXPR_POP       - Pop value from expression stack
-    ;   AH=$22: EXPR_PEEK      - Peek at top of stack
-    ;   AH=$23: EXPR_CLEAR     - Clear expression stack
-    ;   AH=$24: EXPR_DEPTH     - Get current stack depth
-    ;
-    ; === PROGRAM LINE MANAGEMENT (AH=$30-$3F) ===
-    ; $30-$37: Search/Navigate
-    ;   $30: LINE_FIND          - Find line by number (forward)
-    ;   $31: LINE_NEXT          - Get next line
-    ;   $32: LINE_FIND_REVERSE  - Find line by number (backward)
-    ;   $33: LINE_PREV          - Get previous line
-    ; $36-$39: Modify
-    ;   $36: LINE_INSERT        - Insert or replace line
-    ;   $37: LINE_DELETE        - Delete line by number
-    ;   $38: LINE_REMOVE_SPACE  - Add space for new program line
-    ;   $39: LINE_MAKE_SPACE    - remove unused line space
-    ; $3A-$3F: Utility
-    ;   $3A: LINE_FIRST         - Get first line
-    ;   $3B: LINE_CLEAR_ALL     - Clear entire program (NEW)
-    ;   $3C: LINE_COUNT         - Count total lines
-    ;   $3F: PROGRAM_END        - ELM points to end of program
-    ;
-    ; === GOSUB/RETURN STACK (AH=$40-$4F) ===
-    ;   AH=$40: GOSUB_PUSH     - Push return address for GOSUB
-    ;   AH=$41: GOSUB_POP      - Pop return address for RETURN
-    ;   AH=$42: GOSUB_CLEAR    - Clear GOSUB stack
-    ;
-    ; === FOR/NEXT STACK (AH=$50-$5F) ===
-    ;   AH=$50: FOR_PUSH       - Push FOR loop context
-    ;   AH=$51: FOR_POP        - Pop FOR loop context
-    ;   AH=$52: FOR_PEEK       - Peek at current FOR loop
-    ;   AH=$53: FOR_CLEAR      - Clear FOR stack
-    ;   AH=$54: FOR_FIND_VAR   - Find FOR loop by variable letter
-    ;
-    ; === INPUT/OUTPUT HELPERS (AH=$60-$6F) ===
-    ;   AH=$60: IO_GETCHAR     - Get next character from input buffer
-    ;   AH=$61: IO_PUTCHAR     - Output character to screen
-    ;   AH=$62: IO_GETNUM      - Parse number from input
-    ;   AH=$63: IO_PUTNUM      - Output number to screen
-    ;   AH=$64: IO_NEWLINE     - Output CR/LF
-    ;   AH=$65: IO_GETLINE     - Get line of input from user
-    ;   AH=$66: IO_PRINT_STR   - Print string at pointer
-    ;
-    ; === STRING/TOKEN HELPERS (AH=$70-$8F) ===
-    ;   AH=$70: STR_COMPARE    - Compare strings for keyword matching
-    ;   AH=$71: STR_TO_UPPER   - Convert string to uppercase
-    ;   AH=$72: STR_SKIP_SPACE - Skip whitespace in ELM string
-    ;   AH=$73: STR_IS_DIGIT   - Check if character is digit
-    ;   AH=$74: STR_IS_ALPHA   - Check if character is letter
-    ;   AH=$75: STR_LENGTH     - Get string length
-    ;   AH=$76: STR_COPY       - Copy string from src to dst
-    ;   AH=$77: STR_CONCAT     - Concatenate two strings
-    ;   AH=$78: STR_LEFT       - Extract left N characters (LEFT$)
-    ;   AH=$79: STR_RIGHT      - Extract right N characters (RIGHT$)
-    ;   AH=$7A: STR_MID        - Extract middle substring (MID$)
-    ;   AH=$7B: STR_CHR        - Convert byte to character (CHR$)
-    ;   AH=$7C: STR_ASC        - Convert character to byte (ASC)
-    ;   AH=$7D: STR_VAL        - Convert string to number (VAL)
-    ;   AH=$7E: STR_STR        - Convert number to string (STR$)
-    ;   AH=$7F: STR_FIND       - Find substring within string (INSTR)
-    ;   AH=$80: STR_LTRIM      - Trim leading whitespace
-    ;   AH=$81: STR_RTRIM      - Trim trailing whitespace
-    ;   AH=$82: STR_TRIM       - Trim both leading and trailing whitespace
-    ;   AH=$83: STR_REVERSE    - Reverse a string
-    ;   AH=$84: STR_REPEAT     - Repeat character N times (STRING$)
-    ;   AH=$85: STR_SPLIT      - Split string at delimiter
-    ;   AH=$86: STR_REPLACE    - Replace substring with another
-    ;   AH=$87-$8F: (Reserved for future string operations)
-    ;
-    ; === ARITHMETIC/LOGIC HELPERS (AH=$90-$9F) ===
-    ;   AH=$90: MATH_ADD       - Pop two values, push sum
-    ;   AH=$91: MATH_SUB       - Pop two values, push difference
-    ;   AH=$92: MATH_MUL       - Pop two values, push product
-    ;   AH=$93: MATH_DIV       - Pop two values, push quotient
-    ;   AH=$94: MATH_NEG       - Negate top of stack
-    ;   AH=$95: MATH_RND       - Generate random number
-    ;   AH=$96-$9F: (Reserved)
-    ;
-    ; === COMPARISON HELPERS (AH=$A0-$AF) ===
-    ;   AH=$A0: CMP_EQ         - Compare equal
-    ;   AH=$A1: CMP_NE         - Compare not equal
-    ;   AH=$A2: CMP_LT         - Compare less than
-    ;   AH=$A3: CMP_GT         - Compare greater than
-    ;   AH=$A4: CMP_LE         - Compare less than or equal
-    ;   AH=$A5: CMP_GE         - Compare greater than or equal
-    ;   AH=$A6-$AF: (Reserved)
-    ;
-    ; === ERROR HANDLING (AH=$B0-$BF) ===
-    ;   AH=$B0: ERROR_SET      - Set error flag and message
-    ;   AH=$B1: ERROR_GET      - Get current error code
-    ;   AH=$B2: ERROR_CLEAR    - Clear error flag
-    ;   AH=$B3: ERROR_PRINT    - Print error message
-    ;   AH=$B4-$BF: (Reserved)
-    ;
-    ; === IL INTERPRETER CORE (AH=$F0-$FF) ===
-    ;   AH=$F0: IL_INIT        - Initialize IL interpreter
-    ;   AH=$F1: IL_LOAD        - Load IL code into memory
-    ;   AH=$F2: IL_FETCH       - Fetch next IL instruction
-    ;   AH=$F3: IL_DISPATCH    - Dispatch IL instruction
-    ; ============================================================================
-== INT 10h - Terminal Services
-; ============================================================================
-; INT 10h - KEYBOARD / TERMINAL SERVICES
-; PC BIOS-style keyboard interrupt handler
-; ============================================================================
-; Function dispatch via AH register:
-;   AH=00h: Read character (non-blocking)
-;   AH=01h: Check if key available (in keyboar buffer)
-;   AH=02h: Read character (blocking)
-;   AH=03h: Get keyboard flags/shift state
-;   AH=04h: Clear keyboard buffer
-;   AH=05h: Push character into buffer
-;   AH=10h: Clear screen (blank characters only)
-;   AH=11h: Write character at cursor location
-;   AH=12h: Read character at cursor location
-;   AH=13h: Set color data at cursor location
-;   Ah=14h: Get color data at cursor location
-;   AH=15h: Set cursor position
-;   AH=16h: Get cursor position
-;   AH=17h: Write character at cursor (teletype)
-;   AH=18h: Write string at cursor
-;   Ah=19h: Read string between X,Y and cursor
-;   AH=1Ah: Carriage Return
-;   AH=1Bh: Issue Linefeed
-;   AH=1Ch: Scroll screen up (linefeed_push forced linefeed)
-;   AL=20h: Cursor Left (move cursor left one column)
-;   AL=21h: Cursor Right (move cursor right one column)
-;   AL=22h: Cursor Up (move cursor up one row)
-;   AL=23h: Cursor Down (move cursor down one row)
-;   AL=24h: Bell (audible beep - optional)
-;   AL=25h: Backspace (move left and erase character)
-;   AL=26h: Delete (pull line left from cursor to end of line)
-;   AL=27h: Tab (move to next tab stop)
-;   AL=29h: Home (move cursor to 0,0)
-;   AL=30h: Clear to End of Line (erase from cursor to end of line)
-;   AL=31h: Clear to End of Screen (erase from cursor to end of screen)
-;   AL=32h: Insert Line (insert blank line at cursor row)
-;   AL=33h: Delete Line (delete line at cursor row)
-;   AH=40h: Set video mode
-;   AH=41h: Get current video mode
-;   AH=42h: Get video parameters (rows, cols)
-=== Keyboard Services
-NOTE: call numbers have been changed, update pending. See table above for the current call numbers.
-=== AH=00h: Read character (non-blocking)
-* returns character code in AL and keyboard flags in BL.
-=== AH=01h: Read character (blocking)
-* returns character code in AL, keyboard flags in BL, and time spent waiting in ms in C
-=== AH=02h: Get keyboard flags
-* returns keyboard flags in AL.
-=== AH=03h: Check if key available
-* returns the number of keys waiting in AL. I.E. 0=no keys available, 1+= has keys waiting.
-=== AH=01h: Set cursor shape
-=== AH=02h: Set cursor position
-=== AH=03h: Get cursor position
-=== AH=0Eh: Write character (teletype)
-=== AH=13h: Write string
-=== AH=40h: Set video mode
-* Returns: AL is 00 on success, 01 if the mode failed to init.
-Available modes:
-* Mode 0: 22x23 console
-* Mode 1: 40x25 console
-* Mode 2: 80x25 console
-* Mode 3: still thinking, graphics, or superterminal? 1280x800 "128x40"font via 10x20 charset??
-== INT 12h - String Services
-=== AH=00h: strlen
-=== AH=01h: strcpy
-=== AH=02h: strcmp
-=== AH=03h: strcat
-=== AH=04h: atoi
-=== AH=05h: itoa
-== INT 13h - Math Services
-=== AH=00h: Multiply 16-bit
-=== AH=01h: Divide 16-bit
-=== AH=02h: Random number
-=== AH=03h: Absolute value
-== INT 14h - Memory Services
-=== AH=00h: memcpy
-=== AH=01h: memset
-=== AH=02h: memcmp
-== INT 15h - File/Storage (future)