SuperBASIC Memory Map

2024-03-17T17:53:45Z

201.137.92.72: /* Memory Map under BASIC */

=== Memory Map under BASIC ===
{| class="wikitable sortable"
|+ Caption text
|-
! Initial Address !! End Address !! Description !! Bytes
|-
| $0000|| -|| MMU Control Register || 1
|-
| $0001|| -|| I/O Control Register || 1
|-
| $0002|| $0007|| Free Zero Page Addresses || 6
|-
| $0008|| $000F|| MMU Control Addresses || 8
|-
| $0010|| $002F|| Free Zero Page Addresses || 32
|-
| $0030|| $003F|| Used Zero Page Addresses for (xx),Y Addressing || 16
|-
| $0040|| $0041 || Current Address on screen of start of line || 2
|-
| $0042|| $004F|| Avaliable Zero Page Addresses || 14
|-
| $0050|| $00AF|| Number / Floating Point Stack for 16 numbers || 96
|-
| $00B0||$00EF|| Available Zero Page || 64
|-
| $00F0|| $00FF|| Kernel Arguments in Zero Page* || 16
|-
| $0100|| $01FF|| Hardware Stack of 6502 || 256
|-
| $0200|| $0228|| Basic mini-Kernel memory || 40
|-
| $0229|| $03FF|| Available Low Memory | Buffer area by Sound Command in BASIC (available if not using this command) || 470
|-
| $0400|| $041F|| Control Storage first 8 bytes control syntax highlighting || 32
|-
| $0420|| $0814|| Memory Storage || 1012
|-
| $0814|| $0FFF|| Available Low Memory || 2027
|-
| $1000|| $1FFF|| SuperBASIC Identifier Tables, allocated memory, string vars, stack || 4kb
|-
| $2000|| $77FF|| SuperBASIC Program Tokenized Code (grows Upward) || 22kb
|-
| $7800|| $7FFF|| Top 2k of SuperBASIC Program tokenize code or used for ML routines in low memory || 2kb
|-
| $8000|| $BFFF|| SUPERBASIC CODE || 16kb
|-
| $C000|| $DFFF|| I/O Memory Pages / Underlying Kernel Code (Selectable with I/O control Register)|| 8kb
|-
| $E000|| $FFEF|| KERNEL CODE || 8176
|-
| $FFF0|| $FFFF|| Reset Vectors and NMI / IRQ / BRK Vectors || 16
|-
| $01:0000|| $02:2BFF|| Default Memory used by BASIC bitmap graphics || 75kb
|-
| $02:2C00|| $02:7FFF|| Available High Memory || 21kb
|-
| $02:8000|| $02:F000|| Available High Memory | Used for BASIC Cross Development w/PC or MAC (or Available High Memory)|| 32k
|-
| $03:0000|| $03:7FFF|| Used for Sprite Data in BASIC || 32kb
|-
| $03:8000|| $03:FFFF|| Available High Memory | Unless not running from Flash, Used for ROM Images|| 32k
|-
| $04:0000|| $07:DFFF|| Available High Memory || 248kb
|-
| $07:E000|| $07:FFFF|| Available High Memory | Being considered to be Reserved for Environmental Variables || 8Kb
|-
| $10:0000|| $13:FFFF|| Cartridge Expanded Memory (addresable only by CPU) || 256kb
|-
| $14:0000|| $1F:FFFF|| Future Expansions? || 768kb
|}

=== *Detail of Kernel Arguments in Zero Page (TBC!) ===
{| class="wikitable"
|+
!Initial Address
!End Address
!Description
!bytes
|-
|$F0
|$F1
|Kernel Event Struct Pointer - points to an 8 byte buffer with a "kernel event" structure
|2 bytes
|-
|$F3
|
|Kernel File stream number (Read or Write)
|1 byte
|-
|$F4
|
|Kernel File buffer length (Read or Write)
|1 byte
|-
|$F5
|$FA
|???
|6 bytes
|-
|$FB
|$FC
|Kernel Buffer Address Pointer - Multiple purpouse buffer area for recv/send data from Kernel Events
|2 bytes
|-
|$FD
|
|Kernel Buffer Length
|1 byte
|-
|$FE
|$FF
|Unknown
|2 bytes
|}

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SuperBASIC Memory Map