Module spectrusty_formats::sna

SNA snapshot format utilities.

48k SNA file (LSB first):

offset	size	description
0	1	register: I
1	6	registers: HL’, DE’, BC’
7	2	registers: AF’
9	6	registers: HL, DE, BC
15	4	registers: IY, IX
19	1	interrupt flags: bit 1=IFF1, bit 2=IFF1)
20	1	register: R
21	4	registers: AF
23	4	register: SP
25	1	interrupt mode: 0=IM0, 1=IM1, 2=IM2
26	1	border color: 0..=7
27	49152	bytes: RAM 16384..=65535

Total size: 49179 bytes

128k extended SNA file:

offset	size	description
0	27	48k SNA header
27	16384	bytes: RAM page 1, bank 5
16411	16384	bytes: RAM page 2, bank 2
32795	16384	bytes: RAM page 3, currently paged bank
49179	2	register: PC
49181	1	byte: last OUT to 0x7ffd
49182	1	byte: TR-DOS ROM 1=paged, 0=not paged
49183	*16384	bytes: remaining RAM banks in ascending order

Total size:

• 131103 bytes if RAM page 3 is not one of bank 5 or bank 2
• 147487 bytes if RAM page 3 is bank 5 or bank 2 (included twice)

Constants

SNA_LENGTH

The length in bytes of the 48k SNA file.

Functions

load_sna

Loads an SNA file from rd into the provided snapshot loader implementing SnapshotLoader.

load_sna48

Loads a 48k SNA file from rd into the provided snapshot loader implementing SnapshotLoader.

read_sna48

Reads a 48k SNA file and inserts its content into provided memory and configures the Cpu. Returns a border color on success.

save_sna

Saves an SNA file into wr from the provided reference to a snapshot struct implementing SnapshotCreator.