The ARM Architecture – From Sunk to Success Event as iCalendar

(Science Event Tags, Computer Science, Seminars)

19 June 2018

12 - 1pm

Venue: Building 423 Room 340 (Conference Centre)

Location: 22 Symonds Street, Faculty of Engineering, City Campus

Host: Department of Computer Science

Dave Jaggar

Speaker: Dave Jaggar, ARM’s former Head of Architecture Design


In the late 1980’s Acorn, a British one-hit-wonder computer company, developed its own workstation microprocessor, the Acorn RISC Machine (ARM).

By the end of 1990 Acorn was down a very dark financial alley, and the ARM processor, which may well have been the worst CPU architecture ever conceived, was practically extinct. Acorn’s twelve man VLSI design team, minus the two original CPU designers, were cast out to fend for themselves, provisioned with only 18 months of financial rations from Apple.

When Dave Jaggar joined the new company in the summer of 1991, with the ink not quite dry on his Master’s thesis, he thought perhaps it was the worst move since Martin Luther journeyed to Rome.

However after twelve months he was given free rein to redefine the processor, mostly because the company couldn’t afford anyone better. To the Advanced RISC Machine, as the company was renamed, he hastily added a second instruction set which sidestepped many of the problems inherited from the original.

Over the next eight years Dave systematically defined the entire 32-bit ARM architecture, enabling it to be the popular embedded controller for the digital revolution we know today, with over 20 billion units shipped annually, over 80% of which benefit from the compressed instruction format he added almost 25 years ago.

About our speaker

Dave Jaggar was ARM’s Head of Architecture Design in Cambridge UK for six years.

During Dave’s time at ARM he carefully defined the processor architecture, firstly giving it a second integer instruction set which made it excellent for embedded control, added on-chip debug so it could be buried in a SoC, defined a new floating point instruction set, and rebuilt the system architecture so it could run Unix-like OSes properly.

He is the Founding Director of the ARM Austin Design Center in Texas, where he worked for 3 years, where about half of the A series chips for phones are still designed, and he authored the orginal ARM Architectural Reference Manual. Dave is now retired and lives in Christchurch.