VICE Manual - 8 Snapshots

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# 8 Snapshots

Every VICE emulator has a built-in snapshot feature, that saves the complete emulator state into one file for later use. You can therefore save the emulator state - including the state of the game you are playing for example - in a single file.

## 8.1 Snapshot usage

A snapshot is one file containining the complete emulator state. A snapshot file can be generated by selecting the "Save snapshot" command at any time. This will pop up a requester from which you can specify whether the snapshot should also contain the disk and ROM status.

A snapshot file can be used to restore the emulator state by selecting the `load snapshot` menu entry at any time. Unfortunately attached ROM images/cartridges are only supported in the VIC20, the PET and the CBM-II emulators at this time.

The memory configuration of the emulator is saved in the snapshot file as well. This configuration is restored when the snapshot is loaded.

A quick snapshot can now be made by pressing the `M-F11` key and reloaded by pressing the `M-F10` key.

## 8.2 Snapshot format

A snapshot file consists of several modules of mostly different types. Each module has a name and saves the state of an entity like a CIA, the CPU, or the memory.

### 8.2.1 Emulator modules

This section lists the modules that are contained in each of the emulators snapshot files.

#### 8.2.1.1 x64 modules

The modules in the x64 emulator are:

Name | Type | Description
MAINCPU | 6502 | The Main CPU - although it is a 6510, only the 6502 core is saved here
C64MEM | Memory | Holds the RAM contents of the C64. Also the CPU I/O register contents are saved here.
C64ROM | ROM images | Dump of the system ROMs
VIC-II | 656* | The VIC-II of the C64/128
CIA1 | 6526 | The CIA for the interrupts and the keyboard
CIA2 | 6526 | The CIA for the userport, IEC-bus and RS232.
SID | 6581 | The SID sound chip of the C64/C128
REU* |  | The RAM Extension Unit state (optional)
ACIA1 | 6551 | An ACIA (RS232 interface) at $DE00 (optional)
TPI | 6525 | A TPI at $DF00 for a parallel IEEE488 interface (optional)
* | Drive modules | The emulated drive(s) have their own modules see section 8.2.1.6 Drive modules

Some of the modules are optional and are only saved if the specific feature is enabled at save-time. If the module is found when restoring the state the optional features are enabled, and disabled otherwise.

#### 8.2.1.2 x128 modules

The modules in the x128 emulator are:

Name | Type | Description
MAINCPU | 6502 | The Main CPU - although it is a 6510, only the 6502 core is saved here
C128MEM | Memory | Holds the RAM contents of the C64. Also the CPU I/O register contents are saved here.
C128ROM | ROM images | Dump of the system ROMs
VIC-II | 656* | The VIC-II of the C64/128
CIA1 | 6526 | The CIA for the interrupts and the keyboard
CIA2 | 6526 | The CIA for the userport, IEC-bus and RS232.
SID | 6581 | The SID sound chip of the C64/C128
ACIA1 | 6551 | An ACIA at $DE00 (optional)
TPI | 6525 | A TPI at $DF00 for a parallel IEEE488 interface (optional)
* | Drive modules | The emulated drive(s) have their own modules see section 8.2.1.6 Drive modules

Some of the modules are optional and are only saved if the specific feature is enabled at save-time. If the module is found when restoring the state the optional features are enabled, and disabled otherwise.

Not yet supported are the 80 column video chip, cartridges and RAM expansion unit.

#### 8.2.1.3 xvic modules

The modules in the xvic emulator are:

Name | Type | Description
MAINCPU | 6502 | The Main CPU
VIC20MEM | Memory | Holds the RAM contents of the VIC20.
VIC20ROM | ROM images | Holds the ROM images of the VIC20, including possibly attached cartridges
VIC-I | 656* | The VIC-I of the VIC20
VIA1 | 6522 | The VIA for the interrupts and the keyboard
VIA2 | 6522 | The VIA for the userport, IEC-bus and RS232.
* | Drive modules | The emulated drive(s) have their own modules see section 8.2.1.6 Drive modules

#### 8.2.1.4 xpet modules

The modules in the xpet emulator are:

Name | Type | Description
MAINCPU | 6502 | The Main CPU
PETMEM | Memory | Holds the RAM contents of the PET.
PETROM | ROM images | Holds the ROM images of the PET, including possibly attached cartridges
CRTC | 6545 | The CRTC of the PET. This is also included if it is a dump of a PET without CRTC, because the video state is saved here anyway.
PIA1 | 6520 | The PIA for the interrupts, tape and the keyboard
PIA2 | 6520 | The PIA for the IEEE488-bus
VIA | 6522 | The VIA for IEEE488, userport, sound
ACIA1 | 6551 | The ACIA for the SuperPET. This module is optional.
DWWPIA | 6520 | The PIA for the DWW hires board.
CPU6809 | 6809 | The extra CPU in the SuperPET. This module is optional.
* | Drive modules | The emulated drive(s) have their own modules see section 8.2.1.6 Drive modules

#### 8.2.1.5 xcbm2 and xcbm5x0 modules

The modules in the xcbm2 and xcbm5x0 emulators are:

Name | Type | Description
MAINCPU | 6502 | The Main CPU - although it is a 6509, only the 6502 core is saved here
CBM2MEM | Memory | Holds the RAM contents of the CBM-II models. Also holds the exec-bank and indirection bank registers
C500DATA |  | Holds additional state information necessary for the C500 (e.g. cycles till the next IRQ)
CBM2ROM | Memory | optional. Holds the ROM images.
CRTC | 6545 | The video chip for the C6*0 and C7*0 models (only those models).
VIC-II | 656? | The video chip for the C5*0 models (only the C5*0 models).
CIA1 | 6526 | The CIA for IEEE 488 and userport.
TPI1 | 6525 | TPI 1 for IEEE488
TPI2 | 6525 | TPI 2 for interrupts and keyboard.
ACIA1 | 6551 | The RS232 interface
SID | 6581 | The CBM2s SID sound chip
* | Drive modules | The emulated drive(s) have their own modules see section 8.2.1.6 Drive modules

#### 8.2.1.6 Drive modules

The modules for the real disk drive emulation are included in the emulator when the emulation is enabled during the writing of the snapshot.

Name | Type | Description
*CPU | 6502 | The Drive 0 CPU
* | * | *

### 8.2.2 Module formats

This section shows the basic module framework and the contents of the different types of modules.

The single chip modules contain the chip state, not the state of the emulator. We tried to make the format as implementation-independent as possible, to allow reuse of snapshots in later versions of this emulator, or even in other emulators.

#### 8.2.2.1 Terminology

In this section we use certain abbreviations to define the types of the data saved in the snapshot.

`BYTE`
  8 bit integer.
`WORD`
  16 bit integer. Saved with low-byte first, high-byte last.
`DWORD`
  32 bit integer. Saved with low-word first, then high-word. Each word saved with its low-byte first.
`ARRAY`
  Array of BYTE values. Length depends on the description.

The tables for the single modules state the type, name and description of the data saved in the modules. The data is saved in the order it is in the tables, so no offset is given.

#### 8.2.2.2 Module framework

The VICE snapshot file starts with the magic string and includes the fileformat version number.

Type | Name | Description
19 BYTE | MAGIC | "VICE Snapshot File\032", padded with 0
BYTE | VMAJOR | fileformat major version number
BYTE | VMINOR | fileformat minor version number
16 BYTE | MACHINENAME | Name of emulated machine, like "PET", "CBM-II", "VIC20", "C64" or "C128". zerobyte-padded.

The file header is followed by a number of different snapshot modules.

Each module has a header with the information given in the table below. The header includes two version numbers, VMAJOR and VMINOR. Modules with the same VMAJOR should be able to be exchanged. I.e. higher VMINOR numbers only append to the data for lower VMINOR. This additional data is ignored by older restore routines. The other way around newer restore routines must accept the fewer info from lower VMINOR dumps. Changes in VMAJOR might introduce any incompatibility you like, but that's what VMAJOR is for after all :-)

Type | Name | Description
16 BYTE | MODULENAME | The name of the module in ASCII, padded with 0 to 16 byte.
BYTE | VMAJOR | major version number
BYTE | VMINOR | minor version number
DWORD | SIZE | size of the module, including this header

#### 8.2.2.3 CPU 6502 module

This module saves the core 6502 state. You will find a clock value there. All other modules save their own clock values relative to this value. However, the drive modules save their clocks relative to their appropriate CPUs of course.

Warning: This module is still under construction and saves some information that is not sure to be VICE-independent. If in doubt, read the source.

Type | Name | Description
DWORD | CLK | the current CPU clock value. All other clock values are relative to this.
BYTE | AC | Accumulator
BYTE | XR | X index register
BYTE | YR | Y index register
BYTE | SP | Stack Pointer
WORD | PC | Programm Counter
BYTE | ST | Status Registers
DWORD | LASTOPCODE | ?
DWORD | IRQCLK | absolute CLK when the IRQ line came active
DOWRD | NMICLK | absolute CLK when the NMI line came active
DWORD | ? | ?
DWORD | ? | ?

#### 8.2.2.4 CPU 6809 module

This module saves the core 6809 state. You will find a clock value there. All other modules save their own clock values relative to this value. However, the drive modules save their clocks relative to their appropriate CPUs of course.

Warning: This module is still under construction and saves some information that is not sure to be VICE-independent. If in doubt, read the source.

Type | Name | Description
DWORD | CLK | the current CPU clock value. All other clock values are relative to this.
WORD | X | The X register
WORD | Y | The Y register
WORD | U | The U register
WORD | PC | The Program Counter register
BYTE | DP | The Direct Page register
BYTE | CC | The Condition Code register
BYTE | A | The A register
BYTE | B | The B register
|  | The following are for 6309 compatibility:
WORD | V | The V register
BYTE | E | The E register
BYTE | F | The F register

#### 8.2.2.5 CIA module

The CIA 6526 is an I/O port chip with 2 8-bit I/O ports, a shift register, two timers, a Time of Day clock and interrupts.

Version numbers: Major 1, Minor 1.

Type | Name | Description
BYTE | ORA | Output register A
BYTE | ORB | Output register B
BYTE | DDRA | Data direction register A
BYTE | DDRB | Data direction register B
WORD | TAC | Timer A counter value
WORD | TBC | Timer B counter value
BYTE | TOD_TEN | Time of Day - current tenth of second
BYTE | TOD_SEC | Time of Day - current seconds
BYTE | TOD_MIN | Time of Day - current minutes
BYTE | TOD_HR | Time of Day - current hours
BYTE | SDR | contents of shift register
BYTE | IER | mask of enabled interrupt masks
BYTE | CRA | Control register A
BYTE | CRB | Control register B
WORD | TAL | Timer A latch value
WORD | TBL | Timer B latch value
BYTE | IFR | mask of currently active interrupts
BYTE | PBSTATE | Bit 6/7 reflect the PB6/7 toggle bit state. Bit 2/3 reflect the corresponding port bit state.
BYTE | SRHBITS | number of half-bits to still shift in/out SDR
BYTE | ALARM_TEN | Time of Day - alarm tenth of second
BYTE | ALARM_SEC | Time of Day - alarm seconds
BYTE | ALARM_MIN | Time of Day - alarm minutes
BYTE | ALARM_HR | Time of Day - alarm hours
BYTE | READICR | current clock minus the clock when ICR was read last plus 128.
BYTE | TODLATCHED | Bit 0: 1= latched for reading, Bit 1: 2=stopped for writing
BYTE | TODL_TEN | Time of Day - latched tenth of second
BYTE | TODL_SEC | Time of Day - latched seconds
BYTE | TODL_MIN | Time of Day - latched minutes
BYTE | TODL_HR | Time of Day - latched hours
DWORD | TOD_TICKS | clk ticks till next tenth of second
-- | -- | The next items have been added in V1.1
WORD | TASTATE | The state bits of the CIA timer A, according to ciatimer.h
WORD | TBSTATE | The state bits of the CIA timer B, according to ciatimer.h

The last two items have been added in CIA snapshot version 1.1 due to the improved CIA emulation in the newer VICE versions. Some state bits correspond to the CIA state as described in the "A Software Model of the CIA 6526" document by Wolfgang Lorenz, some are delayed versions. For more read the source file `ciatimer.h`.

#### 8.2.2.6 VIA module

The VIA 6522 is the predecessor of the CIA and also an I/O port chip with 2 8-bit I/O ports, a shift register, two timers and interrupts.

Version numbers: Major 1, Minor 0.

Type | Name | Description
BYTE | ORA | Output register A
BYTE | DDRA | Data direction register A
BYTE | ORB | Output register B
BYTE | DDRB | Data direction register B
WORD | T1L | Timer 1 Latch value
WORD | T1C | Timer 1 counter value
BYTE | T2L | Timer 2 latch (8 bit as only lower byte is used)
WORD | T2C | Timer 2 counter value
BYTE | RUNFL | bit 7: timer 1 will generate IRQ on underflow; bit 6: timer 2 will generate IRQ on underflow
BYTE | SR | Shift register value
BYTE | ACR | Auxiliary control register
BYTE | PCR | Peripheral control register
BYTE | IFR | active interrupts
BYTE | IER | interrupt mask
BYTE | PB7 | bit 7 = pb7 state
BYTE | SRHBITS | number of half-bits to shift out on SR
BYTE | CABSTATE | bit 7: state of CA2 pin, bit 6: state of CB2 pin
BYTE | ILA | Port A Input Latch (see ACR bit 0)
BYTE | ILB | Port B Input Latch (see ACR bit 1)

#### 8.2.2.7 PIA module

The PIA 6520 is a chip with two I/O ports (Parallel Interface Adapter) and four additional handshake lines. The chip is pretty the same for Port A and B, only that Port A implements handshake on read operation and port B on write operation.

Version numbers: Major 1, Minor 0.

Type | Name | Description
UBYTE | ORA | Output register A
UBYTE | DDRA | Data Direction Register A
UBYTE | CTRLA | Control Register A
UBYTE | ORB | Output register B
UBYTE | DDRB | Data Direction Register B
UBYTE | CTRLB | Control Register B
UBYTE | CABSTATE | Bit 7 = state of CA2, Bit 6 = state of CB2

#### 8.2.2.8 TPI module

The TPI 6525 is a chip with three I/O ports (Tri-Port-Interface). One of the ports can double as an interrupt prioritizer. Therefore we also have to save the states of the interrupt stack etc.

Version numbers: Major 1, Minor 0.

Type | Name | Description
BYTE | PRA | Port A output register
BYTE | PRB | Port B output register
BYTE | PRC | Port C output register (doubles as IRQ latch register)
BYTE | DDRA | Port A data direction register
BYTE | DDRB | Port B data direction register
BYTE | DDRC | Port C data direction register (doubles as IRQ mask register)
BYTE | CR | Control Register
BYTE | AIR | Active interrupt register
BYTE | STACK | Interrupt stack - the interrupt bits that are not (yet) served.
BYTE | CABSTATE | State of CA/CB pins. Bit 7 = state of CA, Bit 6 = state of CB

#### 8.2.2.9 RIOT module

The RIOT 6532 is a chip with two I/O ports, some RAM and a Timer. The chip contains 128 byte RAM, but the RAM is not saved in the RIOT snapshot, but in the memory section.

Warning: This module is still under construction

Version numbers: Major 0, Minor 0.

Type | Name | Description
BYTE | ORA | Port A output register
BYTE | DDRA | Port A data direction register
BYTE | ORB | Port B output register
BYTE | DDRB | Port B data direction register
BYTE | EDGECTRL | Bit 0/1: A0/A1 address bits written to edgecontrol registers
BYTE | IRQFL | Bit 6/7: A6/A7 IRQ flag register. Bit 0: state of the IRQ line (0=inactive, 1=active)
BYTE | N | timer value
WORD | DIVIDER | Pre-scale divider value (1, 8, 64, or 1024)
WORD | REST | cycles since the last counter change
BYTE | IRQEN | Bit 0: 0= timer IRQ disabled, 1= timer IRQ enabled

#### 8.2.2.10 SID module

Warning: This module is still under construction.

#### 8.2.2.11 ACIA module

The ACIA 6551 is an RS232 interface chip. VICE emulates RS232 connections via `/dev/ttyS*` (Unix) or `COM:` (DOS/WIN - not yet?). When saving a snapshot, those connections are of course lost. The state of the ACIA however is restored if possible. I.e. if a connection is already open when restoring the snapshot, this connection is used instead. If no connection is open, a carrier/DTR drop is emulated.

Version numbers: Major 1, Minor 0.

Type | Name | Description
BYTE | TDR | Transmit Data Register
BYTE | RDR | Receiver Data Register
BYTE | SR | Status Register
BYTE | CMD | Command Register
BYTE | CTRL | Ctrl Register
BYTE | INTX | 0 = no data to tx; 1 = Data is being transmitted; 2 = Data is being transmitted while data in TDR waiting to be put to internal transmit register
DWORD | TICKS | Clock ticks till the next TDR empty interrupt

#### 8.2.2.12 VIC-I module

Warning: This module is still under construction.

#### 8.2.2.13 VIC-II module

Warning: This module is still under construction.

#### 8.2.2.14 CRTC module

Warning: After VICE version 1.0 the CRTC emulation has improved considerably. Especially it is now cycle exact. Therefore a lot more variables must be saved. The snapshot module version jumped from 0.0 to 1.0. Newer versions of VICE can read the old snapshots, but older versions (1.0 and below) cannot read the new snapshots.

Warning: This module is still under construction. Especially the RASTERY and RASTERLINE values might be bogus.

Version numbers: Major 1, Minor 1.

Type | Name | Description
|  | Hardware options
WORD | VADDR_MASK | Mask of the address bits valid when accessing the video memory
WORD | VADDR_CHARSWITCH | If one bit in the video address is used to switch the character generator, it is masked here.
WORD | VADDR_CHAROFFSET | The offset in characters in the character generator that CHARSWITCH switches.
WORD | VADDR_REVSWITCH | If one bit in the video address inverts the screen, it is masked here.
WORD | CHARGEN_MASK | size of character generator in byte - 1
WORD | CHARGEN_OFFSET | offset given by external circuitry
BYTE | HW_CURSOR | external hardware cursor circuitry enabled
BYTE | HW_COLS | number of displayed columns during one character clock cycle
BYTE | HW_BLANK | set if the hardware blank feature is available
|  | CRTC register
20 BYTE | REGISTERS | register DUMP of the CRTC registers 0-19.
|  | CRTC internal registers
BYTE | REGNO | The current index in the CRTC register file
BYTE | CHAR | The current cycle within the current rasterline
BYTE | CHARLINE | The current character line
BYTE | YCOUNTER | The current rasterline in the character
BYTE | CRSRCNT | Framecounter for the blinking cursor
BYTE | CRSRSTATE | if set the hardware cursor is visible
BYTE | CRSRLINES | set if ycounter is within the active cursor rasterlines for a char
WORD | CHARGEN_REL | relative base of currently used character generator in ROM (in byte)
WORD | SCREEN_REL | screen address to load the counter at the beginning of the next rasterline
WORD | VSYNC | number of rasterlines left within vsync; 0 = not in vsync
BYTE | VENABLE | vertical enable flipflop; 1= display, 0= blank.
|  | (VICE-dependent?) variables
WORD | SCREEN_WIDTH | width of the current display window
WORD | SCREEN_HEIGHT | height of the current display window
WORD | SCREEN_XOFFSET | x position where the first character in a line starts in the window...
WORD | HJITTER | ...but only after adding this jitter
WORD | SCREEN_YOFFSET | x position where the first character in a line starts in the window...
WORD | FRAMELINES | expected number of rasterlines for the current frame
WORD | CURRENT_LINE | current rasterline as seen from the CRTC
|  | This value has been added in module version V1.1
BYTE | FLAG | Bit 0: If 1 then bit in VADDR_REVSWITCH must be set for reverse; if 0 then bit must be cleared for reverse.

Here is the reference for the previous CRTC snapshot module. It is outdated and will not be read by this and later versions of VICE.

Version numbers: Major 0, Minor 0.

Type | Name | Description
BYTE | RASTERY | The number of clock cycles from rasterlines start
WORD | RASTERLINE | The current rasterline
WORD | ADDRMASK | The address mask valid for the CRTC. All memory accesses are masked with this value
BYTE | HWFLAG | Bit 0: 1= hardware cursor available. Bit 1: 1= number of columns is doubled by external hardware
20 BYTE | REGISTERS | register DUMP of the CRTC registers 0-19.
BYTE | CRSRSTATE | Hardware cursor: Bits 0-3: frame counter till next crsr line toggle. Bit 7: 1= cursor line active

#### 8.2.2.15 C64 memory module

The C64 memory module actually consists of two modules. The "C64MEM" module is mandatory and contains the RAM dump. The "C64ROM" module is optional and contains a dump of the ROM images.

The size of the C64 memory modules differs with each different memory configuration. The RAM configuration is saved in the snapshot, and restored when the snapshot is loaded. The attached cartridges are not yet(!) saved and not yet restored upon load.

Version numbers: Major 0, Minor 0

The C64MEM module

Type | Name | Description
BYTE | CPUDATA | CPU port data byte
BYTE | CPUDIR | CPU port direction byte
BYTE | EXROM | state of the EXROM line (?)
BYTE | GAME | state of the GAME line (?)
ARRAY | RAM | 64k RAM dump

The C64ROM module

Type | Name | Description
ARRAY | KERNAL | 8k dump of the kernal ROM
ARRAY | BASIC | 8k dump of the basic ROM
ARRAY | CHARGEN | 4k dump of the chargen ROM

#### 8.2.2.16 C128 memory module

The C128 memory module actually consists of two modules. The "C128MEM" module is mandatory and contains the RAM dump. The "C128ROM" module is optional and contains a dump of the ROM images.

The size of the C128 memory modules differs with each different memory configuration. The RAM configuration is saved in the snapshot, and restored when the snapshot is loaded. The attached cartridges are also restored upon load if they have been saved in the snapshot.

Version numbers: Major 0, Minor 0

The C128MEM module

Type | Name | Description
12 BYTE | MMU | dump of the 12 MMU registers
ARRAY | RAM | 128k RAM dump banks 0 and 1

The C128ROM module

Type | Name | Description
ARRAY | KERNAL | 8k dump of the kernal ROM
ARRAY | BASIC | 32k dump of the basic ROM
ARRAY | EDITOR | 4k dump of the editor ROM
ARRAY | 4k CHARGEN | dump of the chargen ROM

#### 8.2.2.17 VIC20 memory module

The VIC20 memory module actually consists of two modules. The "VIC20MEM" module is mandatory and contains the RAM dump. The "VIC20ROM" module is optional and contains a dump of the ROM images.

The size of the VIC20 memory modules differs with each different memory configuration. The RAM configuration is saved in the snapshot, and restored when the snapshot is loaded. The attached cartridges are also restored upon load if they have been saved in the snapshot.

The VIC20MEM module

Version numbers: Major 1, Minor 0

Type | Name | Description
BYTE | CONFIG | Configuration register. Bits 0,1,2,3,5 reflect if the corresponding memory block is RAM (bit=1) or not (bit=0).
ARRAY | RAM0 | 1k RAM dump $0000-$03ff
ARRAY | RAM1 | 4k RAM dump $1000-$1fff
ARRAY | COLORRAM | 2k Color RAM, $9400-$9bff
ARRAY | BLK0 | if CONFIG & 1 then: 3k RAM dump $0400-$0fff
ARRAY | BLK1 | if CONFIG & 2 then: 8k RAM dump $2000-$3fff
ARRAY | BLK2 | if CONFIG & 4 then: 8k RAM dump $4000-$5fff
ARRAY | BLK3 | if CONFIG & 8 then: 8k RAM dump $6000-$7fff
ARRAY | BLK5 | if CONFIG & 32 then: 8k RAM dump $a000-$bfff

The VIC20ROM module

Version numbers: Major 1, Minor 1

Type | Name | Description
BYTE | CONFIG | Bit 0: 1= ROM block $2*** enabled. Bit 1: 1= ROM block $3*** enabled. Bit 2: 1= ROM block $4*** enabled. Bit 3: 1= ROM block $5*** enabled. Bit 4: 1= ROM block $6*** enabled. Bit 5: 1= ROM block $7*** enabled. Bit 6: 1= ROM block $A*** enabled. Bit 7: 1= ROM block $B*** enabled.
ARRAY | KERNAL | 8k KERNAL ROM image $e000-$ffff
ARRAY | BASIC | 16k BASIC ROM image $c000-$dfff
ARRAY | CHARGEN | 4k CHARGEN ROM image
ARRAY | BLK1A | 4k ROM image $2*** (if CONFIG & 1)
ARRAY | BLK1B | 4k ROM image $3*** (if CONFIG & 2)
ARRAY | BLK3A | 4k ROM image $6*** (if CONFIG & 16)
ARRAY | BLK3B | 4k ROM image $7*** (if CONFIG & 32)
ARRAY | BLK5A | 4k ROM image $A*** (if CONFIG & 64)
ARRAY | BLK5B | 4k ROM image $B*** (if CONFIG & 128)
ARRAY | BLK2A | 4k ROM image $4*** (if CONFIG & 4; added in V1.1)
ARRAY | BLK2B | 4k ROM image $5*** (if CONFIG & 8; added in V1.1)

#### 8.2.2.18 PET memory module

The PET memory module actually consists of three modules. The "PETMEM" module is mandatory and contains the RAM dump. The "PETROM" module is optional and contains a dump of the ROM images. The "PETDWW" module is also optional and contains the image of the hires expansion board (if enabled).

The size of the PET memory modules differs with each different memory configuration. The RAM configuration is saved in the snapshot, and restored when the snapshot is loaded.

The PETMEM module

Version numbers: Major 1, Minor 3

Type | Name | Description
BYTE | CONFIG | Configuration value. Bits 0-3: 0= 40 col PET without CRTC; 1= 40 col PET with CRTC; 2 = 80 col PET (with CRTC); 3= SuperPET; 4= 8096; 5= 8296. Bit 6: 1= RAM at $9***. Bit 7: 1= RAM at $A***.
BYTE | KEYBOARD | Keyboard type. 0= UK business; 1= Graphics; 2= German business
BYTE | MEMSIZE | memory size of low 32k in k (possible values 4, 8, 16, 32)
BYTE | CONF8X96 | Value of the 8x96 configuration register
BYTE | SUPERPET | SuperPET config. Bit 0: 1= $9*** RAM enabled. Bit 1: 1= RAM write protected. Bit 2: 1= CTRL register write protected. Bit 3: 0= DIAG pin active. Bits 4-7: RAM block in use.
ARRAY | RAM | 4-32k RAM (not 8296, size depends on MEMSIZE)
ARRAY | VRAM | 2/4k RAM (not 8296, size depends on CONFIG)
ARRAY | EXTRAM | 64k expansion RAM (SuperPET and 8096 only)
ARRAY | RAM | 128k RAM (8296 only)
-- | -- | The following item has been added in V1.1
BYTE | POSITIONAL | bit 0=0 = symbolic keyboard mapping, bit 0=1 = positional mapping.
-- | -- | The following item has been added in V1.2
BYTE | EOIBLANK | bit 0=0 = EOI does not blank screen, bit 0=1 = EOI blanks screen.
-- | -- | The following items have been added in V1.3
WORD | CPU_SWITCH | 6502 / 6809 / PROG
BYTE | VAL, PREVODD, WANTODD | 6702 dongle state information
WORD[8] | SHIFT
BYTE | SuperPET config 2 | Extra bits due to the Super-OS/9 MMU. Bit 5: FIRQ disabled. Bit 6: expansion memory in OS/9 flat mode.

The POSITIONAL item has been added in PETMEM snapshot version 1.1. It is ignored by earlier restore routines (V1.0) and the V1.1 restore routines do not change the current setting when reading a V1.0 snapshot.

In V1.2 the new EOIBLANK variable has been added. This implements the "blank screen on EOI" feature that was previously linked to a wrong resource.

In V1.3 the state for SuperPET has been added.

The PETROM module

Version numbers: Major 1, Minor 1

Type | Name | Description
BYTE | CONFIG | Bit 0: 1= $9*** ROM included. Bit 1: 1= $A*** ROM included. Bit 2: 1= $B*** ROM included. Bit 3: 1= $e900-$efff ROM included. Bit 4: 1= SuperPET ROMs included.
ARRAY | KERNAL | 4k KERNAL ROM image $f000-$ffff
ARRAY | EDITOR | 2k EDITOR ROM image $e000-$e7ff
ARRAY | CHARGEN | 2k CHARGEN ROM image
ARRAY | ROM9 | 4k $9*** ROM image (if CONFIG & 1)
ARRAY | ROMA | 4k $A*** ROM image (if CONFIG & 2)
ARRAY | ROMB | 4k $B*** ROM image (if CONFIG & 4)
ARRAY | ROMC | 4k $C*** ROM image
ARRAY | ROMD | 4k $D*** ROM image
ARRAY | ROME9 | 7 blocks $e900-$efff ROM image (if CONFIG & 8)
-- | -- | The following items have been added in V1.1
ROM6809 | ROM6809 | 24k $A000-$FFFF ROM (if CONFIG & 16)
ARRAY | CHARGEN(2) | upper half of CHARGEN (if CONFIG & 16)

The PETDWW module

For storing the state of the DWW hires expansion board, there is a PETDWWPIA module, and a DWWMEM module.

The former has the same format as the PIA1.

Type | Name | Description
WORD | SIZE | The size of the memory dump that follows, or 0 if DWW disabled.
ARRAY | MEM | The memory in the DWW card, SIZE bytes.

#### 8.2.2.19 CBM-II memory module

The CBM-II memory module actually consists of two modules. The "CBM2MEM" module is mandatory and contains the RAM dump. The "CBM2ROM" module is optional and contains a dump of the ROM images.

The size of the CBM-II memory modules differs with each different memory configuration. The RAM configuration is saved in the snapshot, and restored when the snapshot is loaded.

Version numbers: Major 1, Minor 0

The CBM2MEM module

Type | Name | Description
UBYTE | MEMSIZE | Memory size in 128k blocks (1=128k, 2=256k, 4=512k, 8=1024k)
UBYTE | CONFIG | Bit 0 = $f0800-$f0fff RAM, Bit 1 = $f1000-$f1fff RAM, Bit 2 = $f2000-$f3fff RAM, Bit 3 = $f4000-$f5fff RAM, Bit 4 = $f6000-$f7fff RAM, Bit 5 = $fc000-$fcfff RAM, Bit 6 = is a C500
UBYTE | HWCONFIG | Bit 0/1: model line configuration
UBYTE | EXECBANK | CPUs execution bank register
UBYTE | INDBANK | CPUs indirection bank register
ARRAY | SYSRAM | 2k system RAM $f0000-$f07ff
ARRAY | VIDEO | 2k video RAM $fd000-$fd7ff
ARRAY | RAM | RAM dump, size according to MEMSIZE
ARRAY | RAM08 | if memsize < 1M and CONFIG & 1 : 2k RAM $f0800-$f0fff
ARRAY | RAM1 | if memsize < 1M and CONFIG & 2 : 4k RAM $f1000-$f1fff
ARRAY | RAM2 | if memsize < 1M and CONFIG & 4 : 8k RAM $f2000-$f3fff
ARRAY | RAM4 | if memsize < 1M and CONFIG & 8 : 8k RAM $f4000-$f5fff
ARRAY | RAM6 | if memsize < 1M and CONFIG & 16 : 8k RAM $f6000-$f7fff
ARRAY | RAMC | if memsize < 1M and CONFIG & 32 : 4k RAM $fc000-$fcfff

The RAM* arrays are only saved if the RAM itself is less than 1M. If the memory size is 1M then those areas are taken from the bank 15 area of the normal RAM.

The memory array starts at $10000 if the memory size is less than 512k, or at $00000 if 512k or more. In case of a C510, then the memory array also always starts at $00000.

The CBM2ROM module

Type | Name | Description
UBYTE | CONFIG | Bit 1: 1= $1*** ROM image included. Bit 2: 1= $2000-$3fff ROM image included. Bit 3: 1= $4000-$5fff ROM image included. Bit 4: 1= $6000-$7fff ROM image included. Bit 5: 1= chargen ROM is VIC-II chargen, 0= CRTC chargen.
ARRAY | KERNAL | 8 KERNAL ROM image ($e000-$efff)
ARRAY | BASIC | BASIC ROM image ($8000-$bfff)
ARRAY | CHARGEN | 4k CHARGEN ROM image
ARRAY | ROM1 | 4k cartridge ROM image for $1*** (if CONFIG & 2)
ARRAY | ROM2 | 8k cartridge ROM image for $2000-$3fff (if CONFIG & 4)
ARRAY | ROM4 | 8k cartridge ROM image for $4000-$5fff (if CONFIG & 8)
ARRAY | ROM6 | 8k cartridge ROM image for $6000-$7fff (if CONFIG & 16)

#### 8.2.2.20 C500 data module

The C500 data module contains simple state information not already saved in the other modules.

Version numbers: Major 0, Minor 0

The C500DATA module

Type | Name | Description
DWORD | IRQCLK | CPU clock ticks till next 50Hz IRQ

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