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-
- ATARI 520 ST MEMORY MAP
-
- FF8000-FFFFFF I/O ASSIGNMENTS
-
- FFFC06 6580 ACIA #2 (MIDI)
- FFFC00 MFP 68901 Peripheral Controller
- FF8800 YM2149 (AY-3-8910) Sound
- FF8600 3H-2130 DMA/FDC
- FF8400 RESERVED
- FF8200 2H-2123 Video Controller
- FF8000 Data Configuration
-
- FF0000-FF7FFF UNUSED
- FC0000-FEFFFF 192K System Rom
- FA0000-FBFFFF 128K Expansion Cartridge
- 080000-F9FFFF UNUSED
- 000000-07FFFF 512K RAM
- 078300-07FFFF 32K Video Memory
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-
-
-
- 00242eW YX Postion of mouse
- 00241eW Y position of mouse
- 00241cW X position of mouse
- 002418B Left/Right mouse buttons
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- SYSTEM VARIABLES
-
- 0004c4 _drvbits = 3 if floppies
- 0004bc _hz_200 = 200 Hz timer tick
- 0004b4 buf1 (2 buffer-list pointers)
- 0004a6W _nflops = 0,1, or 2 floppies
- 0004a2 savptr
- 00049ew _____md (for GEMDOS)
- 00048e themd
- 000484B conterm attribute bits
- # 0 enable keyclick
- # 1 enable key-repeat
- # 2 enable bell on ^G
- 000482W _cadload
- 00047e hdv_mediach (h.disk media cha)
- 00047a hdv_boot (to boot from h.disk)
- 000476 hdv_rw (h.disk read/write)
- 000472 hdv_bpb (h.disk bios param bl)
- 00046e hdv_dsb (h.disk state block)
- 00046a hdv_init (h.disk initialize)
- 000466 _frclock (vert. blank count)
- 000462 _vbclock (vert/bl/int/count)
- 00045e screenpt nextptr b/screen mem
- 00045a colorptr pointer to pallette
- 000456 _vblqueue pointer to vblank
- 000454W nvbls number of pointers " "
- 000452W vblsem vert/blank semaphore
- 00044e _v_bas_ad ptr base screen mem
- 00044cW sshiftmd shadow for shiftmd
- =0 320x200x4 (low res)
- =1 640x200x2 (med res)
- =2 640x400x1 (hi res mono)
- 00044aB defshiftmd default video res
- 000448W palmode=0 NTSC, =1 PAL video
- 000446W _bootdev device # booted from
- 000444W _fverify floppy verify flag
- 000442W _timr_ms =$14=20d (50Hz)
- 000440W seekrate default floppy seek
- =0 6ms, =1 12ms,
- =2 2ms, =3 3ms (default)
- 00043a memval2 = $237698aa
- 000436 _memtop top of available mem
- 000432 _membot bottom of " "
- 00043a memval2 = $237698aa
- 000436 _memtop top of available mem
- 000432 _membot bottom of " "
- 00042e phystop physical top of RAM
- 00042a resvector reset bailout vector
- 000426 resvalid = $31415926
- 000424B memcntlr memory configuration
- =0 256K, =4 512K
- =5 1024K (2 banks)
- 000420 memvalid = $752019f3
- 00040c etv_xtra log.vectors $103-107
- 000408 etv_term process/term $102
- 000404 etv_critic critcal/err $101
- 000400 etv_timer timer handoff $100
-
- All addresses are for longwords (32 bits)
- unless suffixed with W (word=16bits) or
- B (byte=8bits).
-
- VECTORS
- 000000-00003ff Exception Vectors
- 000100-0003ff 192 User-Defined Vectors
- 0000c0-0000ff Unassigned, Reserved
- 000080-0000bf Trap #0-15 Instr Vectors
- 000064-00007f Level 1-7 Interr Vectors
- 000060 Spurious Interrupt
- 000030-00005f Unassigned, Reserved
- 00002c Opcode 1111 Emulation
- 000028 Opcode 1010 Emulation
- 000024 Vector 9 - Trace
- 000020 Vector 8 - Privilege Violation
- 00001c Vector 7 - TRAPV instruction
- 000018 Vector 6 - CHK instruction
- 000014 Vector 5 - Divide by Zero
- 000010 Vector 4 - Illegal Instruction
- 00000c Vector 3 - Address Error
- 000008 Vector 2 - Bus Error
- 000004 Reset-Initial Program Counter
- 000000 Reset-Initial Stack Pointer
-
-
- Comment.........
-
- Note that ROM Addresses are at TOP of 68000 Memory to allow
- user RAM of approx 15.75 Meg.
-
- Note screen RAM (32K) resides at 480K to 512K in memory. Right
- smack in the middle of RAM huh !
-
- Note I/O & Devices are also at TOP of Memory.
-
- ABUSE ST BBS 817 634-7480 300/1200/2400 60+ megs
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