Home » Archimedes archive » Archimedes World » AW-1996-02-Disc2.adf » !Z80Dem_Z80Demo » Docs/FileFormat/SNAformat
Docs/FileFormat/SNAformat
This website contains an archive of files for the Acorn Electron, BBC Micro, Acorn Archimedes, Commodore 16 and Commodore 64 computers, which Dominic Ford has rescued from his private collection of floppy disks and cassettes.
Some of these files were originally commercial releases in the 1980s and 1990s, but they are now widely available online. I assume that copyright over them is no longer being asserted. If you own the copyright and would like files to be removed, please contact me.
| Tape/disk: | Home » Archimedes archive » Archimedes World » AW-1996-02-Disc2.adf » !Z80Dem_Z80Demo |
| Filename: | Docs/FileFormat/SNAformat |
| Read OK: | ✔ |
| File size: | 0508 bytes |
| Load address: | 0000 |
| Exec address: | 0000 |
File contents
(from the docs for Arnt Gulbrandsen's JPP emulator for the PC)
The snapshot file format
This format (filetype SNA) is the format used by the Mirage
Microdriver "Dump" command, and most other emulators
Byte offset Contents
0 i register
1 l' register
2 h' register
3 e' register
4 d' register
5 c' register
6 b' register
7 f' register
8 a' register
9 l register
10 h register
11 e register
12 d register
13 c register
14 b register
15 iy low register
16 iy high register
17 ix low register
18 ix high register
19 bit 2 contains iff2
20 r register
21 flags register
22 a register
23 sp low register
24 sp high register
25 interrupt mode (0, 1 or 2)
26 border colour (0..7).
27..49178 48 kbytes ram dump
When the registers have been loaded a RETN command is required to
start the program.
IFF2 is short for interrupt flip-flop 2, and for all practical
purposes is the interrupt-enabled flag. Set means enabled.
00000000 28 66 72 6f 6d 20 74 68 65 20 64 6f 63 73 20 66 |(from the docs f| 00000010 6f 72 20 41 72 6e 74 20 47 75 6c 62 72 61 6e 64 |or Arnt Gulbrand| 00000020 73 65 6e 27 73 20 4a 50 50 20 65 6d 75 6c 61 74 |sen's JPP emulat| 00000030 6f 72 20 66 6f 72 20 74 68 65 20 50 43 29 0a 0a |or for the PC)..| 00000040 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00000050 20 20 20 20 54 68 65 20 73 6e 61 70 73 68 6f 74 | The snapshot| 00000060 20 66 69 6c 65 20 66 6f 72 6d 61 74 0a 0a 54 68 | file format..Th| 00000070 69 73 20 66 6f 72 6d 61 74 20 28 66 69 6c 65 74 |is format (filet| 00000080 79 70 65 20 53 4e 41 29 20 69 73 20 74 68 65 20 |ype SNA) is the | 00000090 66 6f 72 6d 61 74 20 75 73 65 64 20 62 79 20 74 |format used by t| 000000a0 68 65 20 4d 69 72 61 67 65 20 0a 4d 69 63 72 6f |he Mirage .Micro| 000000b0 64 72 69 76 65 72 20 22 44 75 6d 70 22 20 63 6f |driver "Dump" co| 000000c0 6d 6d 61 6e 64 2c 20 61 6e 64 20 6d 6f 73 74 20 |mmand, and most | 000000d0 6f 74 68 65 72 20 65 6d 75 6c 61 74 6f 72 73 0a |other emulators.| 000000e0 0a 20 42 79 74 65 20 6f 66 66 73 65 74 20 20 20 |. Byte offset | 000000f0 20 43 6f 6e 74 65 6e 74 73 0a 0a 20 20 20 20 30 | Contents.. 0| 00000100 20 20 20 20 20 20 20 20 20 20 69 20 20 72 65 67 | i reg| 00000110 69 73 74 65 72 0a 20 20 20 20 31 20 20 20 20 20 |ister. 1 | 00000120 20 20 20 20 20 6c 27 20 72 65 67 69 73 74 65 72 | l' register| 00000130 0a 20 20 20 20 32 20 20 20 20 20 20 20 20 20 20 |. 2 | 00000140 68 27 20 72 65 67 69 73 74 65 72 0a 20 20 20 20 |h' register. | 00000150 33 20 20 20 20 20 20 20 20 20 20 65 27 20 72 65 |3 e' re| 00000160 67 69 73 74 65 72 0a 20 20 20 20 34 20 20 20 20 |gister. 4 | 00000170 20 20 20 20 20 20 64 27 20 72 65 67 69 73 74 65 | d' registe| 00000180 72 0a 20 20 20 20 35 20 20 20 20 20 20 20 20 20 |r. 5 | 00000190 20 63 27 20 72 65 67 69 73 74 65 72 0a 20 20 20 | c' register. | 000001a0 20 36 20 20 20 20 20 20 20 20 20 20 62 27 20 72 | 6 b' r| 000001b0 65 67 69 73 74 65 72 0a 20 20 20 20 37 20 20 20 |egister. 7 | 000001c0 20 20 20 20 20 20 20 66 27 20 72 65 67 69 73 74 | f' regist| 000001d0 65 72 0a 20 20 20 20 38 20 20 20 20 20 20 20 20 |er. 8 | 000001e0 20 20 61 27 20 72 65 67 69 73 74 65 72 0a 20 20 | a' register. | 000001f0 20 20 39 20 20 20 20 20 20 20 20 20 20 6c 20 20 | 9 l | 00000200 72 65 67 69 73 74 65 72 0a 20 20 20 31 30 20 20 |register. 10 | 00000210 20 20 20 20 20 20 20 20 68 20 20 72 65 67 69 73 | h regis| 00000220 74 65 72 0a 20 20 20 31 31 20 20 20 20 20 20 20 |ter. 11 | 00000230 20 20 20 65 20 20 72 65 67 69 73 74 65 72 0a 20 | e register. | 00000240 20 20 31 32 20 20 20 20 20 20 20 20 20 20 64 20 | 12 d | 00000250 20 72 65 67 69 73 74 65 72 0a 20 20 20 31 33 20 | register. 13 | 00000260 20 20 20 20 20 20 20 20 20 63 20 20 72 65 67 69 | c regi| 00000270 73 74 65 72 0a 20 20 20 31 34 20 20 20 20 20 20 |ster. 14 | 00000280 20 20 20 20 62 20 20 72 65 67 69 73 74 65 72 0a | b register.| 00000290 20 20 20 31 35 20 20 20 20 20 20 20 20 20 20 69 | 15 i| 000002a0 79 20 6c 6f 77 20 72 65 67 69 73 74 65 72 0a 20 |y low register. | 000002b0 20 20 31 36 20 20 20 20 20 20 20 20 20 20 69 79 | 16 iy| 000002c0 20 68 69 67 68 20 72 65 67 69 73 74 65 72 0a 20 | high register. | 000002d0 20 20 31 37 20 20 20 20 20 20 20 20 20 20 69 78 | 17 ix| 000002e0 20 6c 6f 77 20 72 65 67 69 73 74 65 72 0a 20 20 | low register. | 000002f0 20 31 38 20 20 20 20 20 20 20 20 20 20 69 78 20 | 18 ix | 00000300 68 69 67 68 20 72 65 67 69 73 74 65 72 0a 20 20 |high register. | 00000310 20 31 39 20 20 20 20 20 20 20 20 20 20 62 69 74 | 19 bit| 00000320 20 32 20 63 6f 6e 74 61 69 6e 73 20 69 66 66 32 | 2 contains iff2| 00000330 0a 20 20 20 32 30 20 20 20 20 20 20 20 20 20 20 |. 20 | 00000340 72 20 72 65 67 69 73 74 65 72 0a 20 20 20 32 31 |r register. 21| 00000350 20 20 20 20 20 20 20 20 20 20 66 6c 61 67 73 20 | flags | 00000360 72 65 67 69 73 74 65 72 0a 20 20 20 32 32 20 20 |register. 22 | 00000370 20 20 20 20 20 20 20 20 61 20 72 65 67 69 73 74 | a regist| 00000380 65 72 0a 20 20 20 32 33 20 20 20 20 20 20 20 20 |er. 23 | 00000390 20 20 73 70 20 6c 6f 77 20 72 65 67 69 73 74 65 | sp low registe| 000003a0 72 0a 20 20 20 32 34 20 20 20 20 20 20 20 20 20 |r. 24 | 000003b0 20 73 70 20 68 69 67 68 20 72 65 67 69 73 74 65 | sp high registe| 000003c0 72 0a 20 20 20 32 35 20 20 20 20 20 20 20 20 20 |r. 25 | 000003d0 20 69 6e 74 65 72 72 75 70 74 20 6d 6f 64 65 20 | interrupt mode | 000003e0 28 30 2c 20 31 20 6f 72 20 32 29 0a 20 20 20 32 |(0, 1 or 2). 2| 000003f0 36 20 20 20 20 20 20 20 20 20 20 62 6f 72 64 65 |6 borde| 00000400 72 20 63 6f 6c 6f 75 72 20 28 30 2e 2e 37 29 2e |r colour (0..7).| 00000410 0a 20 32 37 2e 2e 34 39 31 37 38 20 20 20 20 20 |. 27..49178 | 00000420 34 38 20 6b 62 79 74 65 73 20 72 61 6d 20 64 75 |48 kbytes ram du| 00000430 6d 70 0a 0a 57 68 65 6e 20 74 68 65 20 72 65 67 |mp..When the reg| 00000440 69 73 74 65 72 73 20 68 61 76 65 20 62 65 65 6e |isters have been| 00000450 20 6c 6f 61 64 65 64 20 61 20 52 45 54 4e 20 63 | loaded a RETN c| 00000460 6f 6d 6d 61 6e 64 20 69 73 20 72 65 71 75 69 72 |ommand is requir| 00000470 65 64 20 74 6f 20 0a 73 74 61 72 74 20 74 68 65 |ed to .start the| 00000480 20 70 72 6f 67 72 61 6d 2e 0a 20 20 49 46 46 32 | program.. IFF2| 00000490 20 69 73 20 73 68 6f 72 74 20 66 6f 72 20 69 6e | is short for in| 000004a0 74 65 72 72 75 70 74 20 66 6c 69 70 2d 66 6c 6f |terrupt flip-flo| 000004b0 70 20 32 2c 20 61 6e 64 20 66 6f 72 20 61 6c 6c |p 2, and for all| 000004c0 20 70 72 61 63 74 69 63 61 6c 20 0a 70 75 72 70 | practical .purp| 000004d0 6f 73 65 73 20 69 73 20 74 68 65 20 69 6e 74 65 |oses is the inte| 000004e0 72 72 75 70 74 2d 65 6e 61 62 6c 65 64 20 66 6c |rrupt-enabled fl| 000004f0 61 67 2e 20 20 53 65 74 20 6d 65 61 6e 73 20 65 |ag. Set means e| 00000500 6e 61 62 6c 65 64 2e 0a |nabled..| 00000508
.