Apple IIGS emulators: Difference between revisions
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==Emulators== | ==Emulators== | ||
{| class="wikitable" style="text-align:center" | {| class="wikitable" style="text-align:center;width:100%" | ||
! | !Name | ||
! | !Platform(s) | ||
! | !Latest version | ||
! | ![[Licensing|License]] | ||
! | !Active | ||
! | ![[Recommended Emulators|Recommended]] | ||
|- | |- | ||
! colspan="7"|PC / x86 | ! colspan="7"|PC / x86 | ||
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| {{✓}} | | {{✓}} | ||
| {{?}} | | {{?}} | ||
|} | |||
==Enhancements== | |||
{| class="wikitable sortable" style="text-align:center;width:100%" | |||
! colspan=2 style="width:50%" | Name | |||
!KEGS | |||
!GSplus | |||
|- | |- | ||
| | |||
| | |||
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|} | |} | ||
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==Graphics Capabilities== | ==Graphics Capabilities== | ||
In addition to RGB emulations of the existing Apple II artefact composite video modes, the IIgs adds 320x200 and 640x200 RGB colour modes; the former in various combinations of 16 colours per line and the latter at 4 colours per line (including a hardware dithering mode that acts a little like 16 colours per line). Each line may use any of 16 palettes, making a total of 256 colours on screen without raster-linked palette changes. | In addition to RGB emulations of the existing Apple II artefact composite video modes, the IIgs adds 320x200 and 640x200 RGB colour modes; the former in various combinations of 16 colours per line and the latter at 4 colours per line (including a hardware [[dithering]] mode that acts a little like 16 colours per line). Each line may use any of 16 palettes, making a total of 256 colours on-screen without raster-linked palette changes. | ||
There is also some support for 'fill mode', in which colour 0 means "repeat the last non-zero colour", designed to aid in fast single-colour fills. | There is also some support for 'fill mode', in which colour 0 means "repeat the last non-zero colour", designed to aid in fast single-colour fills. | ||
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{{Apple}} | {{Apple}} | ||
[[Category:Apple computers]] | |||
[[Category:Computers]] | [[Category:Computers]] | ||
Latest revision as of 04:44, 15 September 2026
| |
| An Apple IIGS PC. | |
| Developer | Apple Computer, Inc. |
|---|---|
| Type | Computers |
| Release date | September 1986 |
| Discontinued | December 1992 |
| Predecessor | Apple II |
| Emulated | ✓ |
The Apple IIGS is a 16-bit PC produced by Apple Computer, Inc. It was created to compete with the Amiga and the Atari ST lines of PCs.
Despite the Apple IIGS name, it is a completely different architecture. The system has a chip called the “Mega II” which is an Apple //e on a chip, making it fully backwards compatible with Apple ][ software.
It was the first machine from Apple to use the Apple Desktop Bus and the first to provide a colour version of QuickDraw since the first colour Macintosh was not available until 1987. However it does not provide a high-resolution square pixel mode.
Emulators
[edit | edit source]| Name | Platform(s) | Latest version | License | Active | Recommended | |
|---|---|---|---|---|---|---|
| PC / x86 | ||||||
| KEGS |   
|
1.38 | GPLv2 (Copyleft) | ✓ | ✓ | |
| GSplus |
|
1.38.0 | GPLv2 (Copyleft) | ✗ | ~ | |
| GSport |
|
0.31 | GPLv2 (Copyleft) | ✗ | ✗ | |
| Sweet16 |
|
3.0.3 | ? | ✗ | ? | |
| MAME | 
|
0.289 | GPLv2 BSD-3-Clause |
✓ | ✗ | |
| Crossrunner |
|
1.1 | ? | ✓ | ? | |
Enhancements
[edit | edit source]| Name | KEGS | GSplus | |
|---|---|---|---|
Processor
[edit | edit source]The central processor is a 65816, a backwards-compatible 16-bit update to the 6502 that was also used in the Super Nintendo. It runs natively at 2.8Mhz but will slow down to ~1Mhz when in classic Apple II emulation mode or when writing to video memory.
Graphics Capabilities
[edit | edit source]In addition to RGB emulations of the existing Apple II artefact composite video modes, the IIgs adds 320x200 and 640x200 RGB colour modes; the former in various combinations of 16 colours per line and the latter at 4 colours per line (including a hardware dithering mode that acts a little like 16 colours per line). Each line may use any of 16 palettes, making a total of 256 colours on-screen without raster-linked palette changes.
There is also some support for 'fill mode', in which colour 0 means "repeat the last non-zero colour", designed to aid in fast single-colour fills.
Colours are selected from a 12-bit RGB 4,096 colour palette; the IIGS therefore has the same total colour range as its contemporaries the Commodore Amiga, the Atari STE and the Acorn Archimedes.
However it is subject to a number of deficiencies: there is a single buffer for video only — double buffering is not supported — and it supports neither hardware scrolling nor hardware sprites; and as all writes into video memory clock the CPU down to 1Mhz these are expensive to perform in software.
Audio Capabilities
[edit | edit source]The IIGS provides a 32-channel wavetable Ensoniq sound chip, which uses 64kb for samples.
The OS by default configures this as 15 stereo channels and uses the remaining two channels as interrupt counters; the IIGS is therefore often described as a 15-channel machine.
