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--- sd:vc-3_system_interrupt_table [2026/03/07 06:17] – appledog
+++ sd:vc-3_system_interrupt_table [2026/03/22 08:45] (current) – removed appledog
@@ 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. This calling convention is not shown here; however, it will be added later and/or some functions may be explained in the [[SD-8516 Programmer's Reference Guide]]. Over time, more information will be added here.
-=== 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, FLD (see calling convention)
-=== Example Code
-<codify armasm>
-LDAL #'A'       ; AL has the variable name
-LDB #1234       ; B has the value to set
-LDAH $11        ; VAR_SET
-INT $05
-LDELM @string   ; address of string containing a number
-LDAH $62        ; IO_GETNUM
-INT $05
-; B contains the number from the string
-</codify>
-== INT 05h - TinyBASIC IL
-<code>
-; ============================================================================
-; INT 05h - "TinyBASIC" Interpretive Language
-; Complete implementation of a TinyBASIC IL + Stellar BASIC extensions
-; ============================================================================
-; Function dispatch via AH register:
-;
-; === 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
-;
-; === NAMED VARIABLE SERVICES (AH=$14-$1F) ===
-;   AH=$14: NVAR_GET    - Find variable by name
-;   AH=$15: NVAR_SET    - Insert or update variable
-;   AH=$16: NVAR_DELETE - Remove variable
-;   AH=$17: NVAR_CLEAR  - Clear all named variables
-;
-; === 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
-;
-; === STACK MANIPULATION (AH=$28-$2F) ===
-;   AH=$25: EXPR_DUP        - Duplicate top of stack
-;   AH=$26: EXPR_SWAP       - Swap top two values
-;   AH=$27: EXPR_DROP       - Drop top value
-;   AH=$28: EXPR_OVER       - Copy second value to top
-;   AH=$29: EXPR_ROT        - Rotate top 3 values
-;
-; === 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 use/publir
-;   AH=$66: IO_PRINT_STR   - Print string at pointer
-;   AH=$67: IO_PROCESS_STRING - Process a string in quotes for printing.
-;   AH=$68: IO_INPUT - for the INPUT command. Simple string input.
-;
-; === 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_RAND      - Generate random integer
-;   AH=$96: MATH_RND       - Generate random number between 0 and 1
-;
-; === ADVANCED MATH (AH=$96-$9F) ===
-;   AH=$9A: MATH_MOD        - Modulo (remainder)
-;   AH=$9B: MATH_ABS        - Absolute value
-;   AH=$9C: MATH_MIN        - Minimum of two values
-;   AH=$9D: MATH_MAX        - Maximum of two values
-;   AH=$9E: MATH_SGN        - Sign (-1, 0, or 1)
-;
-; === COMPARISON HELPERS (AH=$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-$BF: (Reserved)
-;;
-;
-; === MEMORY OPERATIONS (AH=$C0-$CF) ===
-;   AH=$C0: MEM_LOAD_BYTE   - Load byte from [addr on stack]
-;   AH=$C1: MEM_STORE_BYTE  - Store byte to [addr on stack]
-;   AH=$C2: MEM_LOAD_WORD   - Load word from [addr on stack]
-;   AH=$C3: MEM_STORE_WORD  - Store word to [addr on stack]
-;   AH=$C4: ADDR_ADD        - Pointer arithmetic (base + offset)
-;   AH=$C5: ADDR_SCALE      - Scale index (index * size)
-;
-; === LOCAL VARIABLE FRAMES (AH=$D0-$DF) ===
-;   AH=$D0: FRAME_ALLOC     - Allocate stack frame
-;   AH=$D1: FRAME_FREE      - Free stack frame
-;   AH=$D2: LOCAL_GET       - Get local variable by offset
-;   AH=$D3: LOCAL_SET       - Set local variable by offset
-;   AH=$D4: PARAM_GET       - Get function parameter
-;   AH=$D5: PARAM_SET       - Set function parameter
-;
-; === LOGICAL/BITWISE OPERATIONS (AH=$E0-$EF) ===
-;   AH=$E0: LOG_AND         - Logical AND (0/1 values)
-;   AH=$E1: LOG_OR          - Logical OR (0/1 values)
-;   AH=$E2: LOG_NOT         - Logical NOT (0/1 values)
-;   AH=$E3: BIT_AND         - Bitwise AND
-;   AH=$E4: BIT_OR          - Bitwise OR
-;   AH=$E5: BIT_XOR         - Bitwise XOR
-;   AH=$E6: BIT_NOT         - Bitwise NOT (complement)
-;   AH=$E7: BIT_SHL         - Bitwise shift left
-;   AH=$E8: BIT_SHR         - Bitwise shift right
-;
-; === TYPE CONVERSION (AH=$EA-$EF) ===
-;   AH=$EA: CONV_BYTE_WORD  - Convert byte to word (zero-extend)
-;   AH=$EB: CONV_WORD_BYTE  - Convert word to byte (truncate)
-;   AH=$EC: CONV_SIGNED     - Sign-extend byte to word
-; === IL INTERPRETER CORE (AH=$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 05h - PALO ALTO TINY BASIC SYSTEM
-; Memory map and constants
-; ============================================================================
-; *** Note: If you make changes here please reflect them in memorymap.sda
-.equ PATB_TBUF          $01DB00   ; tokenizer buffer (as listed in memory map) CHECKME: not really being used?
-.equ PATB_VARIABLES     $01EE00   ; 26 vars × 2 bytes = 52 bytes ($01EE00-$01EE33)
-.equ PATB_EXPR_STACK    $01EE34   ; Expression stack, 64 bytes ($01EE34-$01EE73)
-.equ PATB_EXPR_SP       $01EE74   ; Expression stack pointer (2 bytes)
-.equ PATB_GOSUB_STACK   $01EE76   ; GOSUB stack, 48 bytes (16 levels × 3 bytes)
-.equ PATB_GOSUB_SP      $01EEA6   ; GOSUB stack pointer (2 bytes)
-.equ PATB_FOR_STACK     $01EEA8   ; FOR stack, 40 bytes (8 levels × 5 bytes)
-.equ PATB_FOR_SP        $01EED0   ; FOR stack pointer (2 bytes)
-.equ PATB_GOTO_TARGET   $01EED2   ; 2 bytes: 0 = no goto, nonzero = target line#
-.equ PATB_STATUS        $01EED4   ; 1 byte
-                                  ; Bit 0: Running (1) / Stopped (0)
-                                  ; Bit 1: Error flag
-                                  ; Bit 2: Break flag
-.equ PATB_RANDSEED      $01EED5   ; 2 bytes
-.equ PATB_PROGRAM_PTR   $01EED7   ; 3 bytes
-.equ PATB_IL_PTR        $01EEDA   ; 3 bytes
-.equ PATB_INPUT_PTR     $01EEDD   ; 3 bytes
-.equ PATB_BANK          $01EEE0   ; 1 byte
-.equ PATB_DIM_NAMEPTR   $01EEE1   ; 3 bytes - saved var name pointer for DIM loop
-.equ PATB_VARTOP        $01EEE4   ; 3 bytes - bottom of variable storage (grows down)
-.equ PATB_DATA_PTR      $01EEE7   ; 3 bytes - for DATA and READ statements
-.equ PATB_MS_PTR        $01EEEA   ; 3 bytes - multiline statement pointer
-; RESERVED: $01EEED-$01EEFF = 19 bytes free
-; Refer to memorymap.sda if these change
-.equ PATB_PROGRAM_BASE  $000100   ; Start of program storage (Bank 3, offset $100)
-.equ PATB_PROGRAM_END   $00FFFF   ; End (almost 64KB for programs)
-</code>
-== INT 10h - Terminal Services
-<code>
-; ============================================================================
-; 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: Print character at cursor (teletype)
-;   AH=18h: Print 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)
-;   AH=20h: Cursor Left (move cursor left one column)
-;   AH=21h: Cursor Right (move cursor right one column)
-;   AH=22h: Cursor Up (move cursor up one row)
-;   AH=23h: Cursor Down (move cursor down one row)
-;   AH=24h: Bell (audible beep - optional)
-;   AH=25h: Backspace (move left and erase character)
-;   AH=26h: Delete (pull line left from cursor to end of line)
-;   AH=27h: Tab (move to next tab stop)
-;   AH=28h: Home (move cursor to 0,0)
-;   AH=29h: Advance Cursor with Line Link Hook (links to term.sda)
-;   links to term.sda:
-;   AH=$2A: int10_cursor_blink -- Blink cursor (main loop)
-;   AH=$2B: int10_cursor_on -- Turn cursor on
-;   AH=$2C: int10_cursor_off -- Turn cursor off
-;   AH=$2D: int10_cursor_toggle -- Toggle cursor
-;   AH=$2E: int10_set_cursor_colors -- Set char/cursor colors
-;   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)
-;   AL=34h: link line
-;   AL=35h:
-;   AL=36h:
-;   AL=37h:
-;   AH=38h: Scroll Line Links
-;   AH=40h: Set video mode
-;   AH=41h: Get current video mode
-;   AH=42h: Get MAX ROWS (mode 0:23, 1:25, 2:25, 3: 30)
-;   AH=43h: Get MAX COLS (mode 0:22, 1:40, 2:80, 3: 120)
-;   AH=44h: Get pointer to VIDEO_TEXT_BASE for current mode (or start of framebuffer for graphics modes)
-;   AH=45h: Get pointer to VIDEO_COLOR_BASE for current mode (or palette space for graphics modes)
-;   AH=46h: is text mode?
-;   AH=47h: get char rom base
-</code>
-== INT 11h - Sound Services
-Please see the interrupt table and function discussion in [[Appendix 5 Sound System]] of the [[SD-8516 Programmer's Reference Guide]].
-== INT 12h - String Services
-* [[INT 12h String Services]]
-== INT 13h - Math Services
-<code>
-; ============================================================================
-; INT 13h - MATH SERVICES
-; Stellar BIOS Math operations interrupt handler
-; ============================================================================
-; Function dispatch via AH register:
-;   AH=00h: Random number (16-bit)
-;   AH=01h: Random number in range
-;   AH=02h: Seed random number generator
-;   AH=03h: Square root (integer)
-;   AH=04h: Power (base^exponent)
-;   AH=05h: Sine (8-bit fixed point)
-;   AH=06h: Cosine (8-bit fixed point)
-;   AH=07h: Tangent (8-bit fixed point)
-;   AH=08h: Arctangent2 (for angles)
-;   AH=09h: Absolute value
-;   AH=0Ah: Min of two values
-;   AH=0Bh: Max of two values
-;   AH=0Ch: Clamp value to range
-;
-; ============================================================================
-</code>
-== INT 18h - Graphics Services
-<code>
-; ============================================================================
-; INT 18h - GRAPHICS SERVICES
-; Stellar BIOS Graphics operations interrupt handler
-; ============================================================================
-; Function dispatch via AH register:
-;   AH=00h: reserved (for set graphics mode see int 10h ah=40h)
-;   AH=01h: Plot MODE 3 pixel (4bpp)
-;   AH=02h: Plot MODE 4 pixel (8bpp)
-;   AH=11h: Get MODE 3 pixel (4bpp)
-;   AH=12h: Get MODE 4 pixel (8bpp)
-;   AH=20h: Clear screen (fill with color)
-;   AH=21h: Draw line
-;   AH=22h: Draw rectangle (outline)
-;   AH=23h: Fill rectangle
-;   AH=24h: Draw circle (outline)
-;   AH=25h: Fill circle
-;   AH=26h: Draw ellipse
-;   AH=30h: Blit sprite/image
-;   AH=40h: Set color mode for video mode
-;   AH=41h: Get current color mode
-;   AH=42h: Set palette entry (AL=0, use 0-15. Anything else, use 0-255)
-;   AH=43h: Get palette entry (AL=0, use 0-15. Anything else, use 0-255)
-;   AH=44h: Load palette (AL=0, use 16color, anything else, all 256. ELM=source for palette data)
-;   AH=45h: Set draw color (deprecated for now)
-;   AH=46h: Flood fill (PAINT) (deprecated for now)
-;   AH=50h: Scroll region
-;   AH=51h: Copy region
-; ============================================================================
-</code>