The Silent Invasion

Acorn RISC Machine or Advanced RISC Machine?

You own an ARM machine! (or several dozen) Over 75% of the embedded device market is powered by ARM ARM is small Requires low power Efficient performance CHEAP TO MANUFACTURE

Jazelle technology Thumb 2 Enhanced DSP Up to 200MHZ As small as 90nm ARM926EJ-S

Odd features of the ARM Model Every instruction has a condition code This means that you don’t necessarily have to branch around. Shifting and rotating can be embedded in other arithmetic instructions. An actually useful interrupt system

Registers ARM is load-store Has 37 registers You can only see 16 in main software mode You can only really use the first 13 R13, R14, and R15 are the stack pointer, link pointer, and the PC respectively

Instruction format Virginia Lo:

NOBODY EXPECTS YOU TO MEMORIZE IT!

Instructions ADD – Standard Addition ADC – Add with carry QADD – Saturated add QDADD – Double saturated add B – Branch… if you don’t know what this does, good luck on the final BL – Branch and link

An odd instruction BX – Branch and exchange BXL – Branch, exchange, and link