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In computing, Aemulor is an emulator of the earlier 26-bit addressing-mode ARM microprocessors. It runs on ARM processors under 32-bit addressing-mode versions of RISC OS. It was written by Adrian Lees and released in 2003. An enhanced version is available under the name Aemulor Pro.

A logo consisting of turquoise text reading ARM above larger blue text reading Aemulator. A stylized picture of a blue square circuit board is behind the text
Original author(s)Adrian Lees
Initial releaseMarch 2003 (2003-03)
Stable release
Operating systemRISC OS
LicenseProprietary commercial software

The software allows Raspberry Pi,[1] Iyonix PC and A9home computers running RISC OS to make use of some software written for older hardware. As of 2012, compatibility with the BeagleBoard single-board computer was under development.


The software's existence was first reported around the time of the announcement of the Iyonix in October 2002.[2][3] A demo version was released in February 2003,[4][5] with the commercial release in March of that year.[6][7][8]

Aemulor Pro was released in 2004. This added enhancements, including support for low colour modes, required by scorewriter Sibelius and many games.[9][10][11] A version for the A9home was released in 2005.[12] The software was exhibited at the 2006 Wakefield Show.[13]

In 2009, author Adrian Lees[14][15] posted on The Icon Bar, showing an early prototype of the software running on the BeagleBoard.[15][16] Progress on further compatibility for the Raspberry Pi single-board computer was announced by Lees on the RISC OS Open forum in 2012.[17] Developer R-Comp was reported in May 2012 to be hoping to make Aemulor available for its BeagleBoard-xM-based ARMini computer.[18]


Sibelius running on the Iyonix

The software provides full 26-bit emulation[6] for applications written in C and ARM assembly language. It employs an XScale-optimised ARM code interpreter, supports SWI emulation from RISC OS 4 to 5, flag preservation and creation of dynamic areas in low memory.[19] Support for running A310Emu is included, allowing users to further emulate earlier versions of the OS, going back to Arthur.[20] As of 2003, due to the memory remapping employed, native 32-bit applications are restricted to a maximum size of 28Mb while Aemulor is running.[21]

The original release included an Easter egg, with a prize of an upgrade to the Pro version for the person who found it.[22][23]

Aemulor Pro adds support for low-bpp screen modes, sound, hardware emulation of VIDC/IOC, an altered memory map and 26-bit filing systems.[19] Some software, such as Sibelius, can be run both in the desktop and in full screen.[9]

Compatible softwareEdit

Title Purpose Vendor/publisher
ArtWorks[24] vector graphics MW Software
Impression[24] desktop publishing Computer Concepts
Sibelius[9] scorewriter Sibelius Software
Spheres of Chaos.[25] video game
StrongED[24] text editor
Zap[24] text editor


  1. ^
  2. ^ Williams, Chris (20 October 2002). "Iyonix 26 bit emulator in development". Drobe. Retrieved 21 June 2012.
  3. ^ "32-bit introduction". IYONIX pc. Castle Technology. Archived from the original on 9 July 2012. Retrieved 29 June 2012.
  4. ^ Williams, Chris (22 February 2003). "South West show news". Drobe. Retrieved 21 June 2012.
  5. ^ Williams, Chris (9 March 2003). "South West show news". Drobe. Retrieved 21 June 2012.
  6. ^ a b Williams, Chris (25 March 2003). "Aemulor sees the light of day". Drobe. Retrieved 27 June 2012.
  7. ^ Hoare, John (25 March 2003). "Aemulor Released". Acorn Arcade. Retrieved 29 June 2012.
  8. ^ Peachey, John (June 2003). "Aemulor in Use". Archive. 16 (9). Retrieved 29 June 2012.
  9. ^ a b c Williams, Chris (12 March 2004). "Aemulor Pro embraces Sibelius". Drobe. Retrieved 21 June 2012.
  10. ^ Mellor, Phil (6 May 2004). "Aemulor Pro is out now". Acorn Arcade. Retrieved 29 June 2012.
  11. ^ Lee, Jeffrey (22 April 2004). "Aemulor Pro-gress". Acorn Arcade. Retrieved 29 June 2012.
  12. ^ Williams, Chris (5 November 2005). "Aemulor for the A9home released". Drobe. Retrieved 21 June 2012.
  13. ^ "Wakefield 2006". RISC World. 6 (6). Retrieved 29 June 2012.
  14. ^ Lees, Adrian. "The homepage of Adrian Lees". Adrian Lees. Retrieved 29 June 2012.
  15. ^ a b Naulls, Peter (20 December 2009). "Aemulor on BeagleBoard". Retrieved 29 June 2012.
  16. ^ Lees, Adrian (20 December 2009). "Aemulor BeagleBoard". TIB forum. The Icon Bar. Retrieved 29 June 2012.
  17. ^ Lees, Adrian (20 June 2012). "Aemulor on the Beagle/Panda boards". ROOL forum. RISC OS Open. Retrieved 29 June 2012.
  18. ^ Proven, Liam (10 May 2012). "Best and the Rest: ARM Mini PCs". Reg Hardware. Retrieved 29 June 2012.
  19. ^ a b "Aemulor Professional". Spellings Computer Services. Archived from the original on 2 February 2014. Retrieved 29 June 2012.
  20. ^ Williams, Chris (19 April 2003). "Aemulor turns to RISC OS 2". Drobe. Retrieved 21 June 2012.
  21. ^ "Inside Aemulor". Foundation RISC User. Retrieved 29 June 2012.
  22. ^ Williams, Chris (5 August 2003). "Aemulor 2.2 upgrade online". Drobe. Retrieved 21 June 2012.
  23. ^ Williams, Chris (19 December 2003). "Aemulor's brief Windows affair discovered". Drobe. Retrieved 21 June 2012.
  24. ^ a b c d Williams, Chris (19 November 2002). "Aemulor: Number of apps working on Iyonix 'growing daily'". Drobe. Retrieved 21 June 2012.
  25. ^ Brett, Paul. "Games World". RISC World. Retrieved 29 June 2012.