Page 3

From C64-Wiki
Jump to: navigation, search

Page 3 covers the memory locations 768-1023 ($0300-03FF). This page area, like Page 2, stores information for use by the Operating System and BASIC; including pointers for BASIC and KERNAL routines. There is also buffer space in this page for the tape I/O, BASIC text input, the keyboard queue, and a small space for user-defined data.

Addresses[edit]

RAM

Hex Address Dec Address Type Contents
$0300 768 Pointer Low Byte address of the Print BASIC Error Message Routine
$0301 769 Pointer High byte address of the Print BASIC Error Message Routine
$0302 770 Pointer Low Byte address of the Main BASIC Program Loop
$0303 771 Pointer High byte address of the Main BASIC Program Loop
$0304 772 Pointer Low Byte address of the routine That Crunches the ASCII Text of Keywords into Tokens
$0305 773 Pointer High byte address of the routine That Crunches the ASCII Text of Keywords into Tokens
$0306 774 Pointer Low Byte address of the routine That Lists BASIC Program Token as ASCII Text
$0307 775 Pointer High byte address of the routine That Lists BASIC Program Token as ASCII Text
$0308 776 Pointer Low Byte address of the routine That Executes the Next BASIC Program Token
$0309 777 Pointer High byte address of the routine That Executes the Next BASIC Program Token
$030A 778 Pointer Low Byte address of the routine That Evaluates a Single-Term Arithmetic Expression
$030B 779 Pointer High byte address of the routine That Evaluates a Single-Term Arithmetic Expression
$030C 780 Value Storage Area for .A Register (Accumulator)
$030D 781 Value Storage Area for .X Index Register
$030E 782 Value Storage Area for .Y Index Register
$030F 783 Value Storage Area for .P (Status) Register
Bit 0 - Carry
Bit 1 - Zero
Bit 2 - Interrupt Disable
Bit 3 - Decimal
Bit 4 - Break
Bit 5 - Unused
Bit 6 - Overflow
Bit 7 - Negative
$0310 784 Value Machine code, 76 ($4C), for assembler command JMP
$0311 785 Pointer Low Byte address of USR routine
$0312 786 Pointer High byte address of USR Routine
$0313 787 Unused
$0314 788 Pointer Low Byte address of the interrupt service routine
$0315 789 Pointer High byte address of the interrupt service routine
$0316 790 Pointer Low Byte address of the BRK instruction interrupt
$0317 791 Pointer High byte address of the BRK instruction interrupt
$0318 792 Pointer Low Byte address of the routine that follows a non-maskable interrupt
$0319 793 Pointer High byte address of the routine that follows a non-maskable interrupt
$031A 794 Pointer Low Byte address of the KERNAL OPEN routine
$031B 795 Pointer High byte address of the KERNAL OPEN routine
$031C 796 Pointer Low Byte address of the KERNAL CLOSE routine
$031D 797 Pointer High byte address of the KERNAL CLOSE routine
$031E 798 Pointer Low Byte address of the KERNAL CHKIN routine
$031F 799 Pointer High byte address of the KERNAL CHKIN routine
$0320 800 Pointer Low Byte address of the KERNAL CKOUT routine
$0321 801 Pointer High byte address of the KERNAL CKOUT routine
$0322 802 Pointer Low Byte address of the KERNAL CLRCHN routine
$0323 803 Pointer High byte address of the KERNAL CLRCHN routine
$0324 804 Pointer Low Byte address of the KERNAL CHRIN routine
$0325 805 Pointer High byte address of the KERNAL CHRIN routine
$0326 806 Pointer Low Byte address of the KERNAL CHROUT routine
$0327 807 Pointer High byte address of the KERNAL CHROUT routine
$0328 808 Pointer Low Byte address of the KERNAL STOP routine
$0329 809 Pointer High byte address of the KERNAL STOP routine
$032A 810 Pointer Low Byte address of the KERNAL GETIN routine
$032B 811 Pointer High byte address of the KERNAL GETIN routine
$032C 812 Pointer Low Byte address of the KERNAL CLALL routine
$032D 813 Pointer High byte address of the KERNAL CLALL routine
$032E 814 Pointer Low Byte address of the user-defined routine
$032F 815 Pointer High byte address of the user-defined routine
$0330 816 Pointer Low Byte address of the LOAD routine
$0331 817 Pointer High byte address of the LOAD routine
$0332 818 Pointer Low Byte address of the SAVE routine
$0333 819 Pointer High byte address of the SAVE routine
$0334-$033B 820-827 Unused
$033C-$03FB 828-1019 Datasette I/O buffer
$03FC-$03FF 1020-1023 Unused