Transcript ARM-processors

ARM processors
Adam Hoover
ARM processors
What is it?
Family of 32-bit microcontroller processors
Who makes it?
ARM has changed their name several times:
Acorn RISC Machines (1985)
Advanced RISC Machines (1990)
ARM Holdings (1998)
What is its niche?
Mid-high level complexity hand-held consumer electronics
PDA’s (1980’s)
Cell phones (1990’s)
Handheld game devices (2000’s)
Example Consumer Products
Nintendo DS
Apple Ipod
TASC ChessMachine
Gameboy advance
Apple Newton PDA
Apple Iphone
Processor design, not a chip
Core design
Chip design & fabrication
ARM licenses core designs to other companies
OEMs can customize chips
ARM provides compilers, development tools,
and debugging tools for chip development
and product development
Nintendo DS
ARM chips (examples)
ARM processor features
ARM1 (1985) to ARM11 and Cortex lines, most having 5+ flavors
ARM7 cores
• Small number of transistors (~35,000)
• No microcode, all instructions hard-wired (no flexibility in ISA)
• 3-stage pipeline (simple fetch-decode-execute)
• 4-8 KB cache memory, typically unified (data/instruction)
• 32-bit ISA (not used for simple control stuff)
• 18-56 MHz clock speed
ARM extensions
• “Thumb” instruction set – 16 bit ISA packed into 32-bit code
• “Jazelle” instruction set – java code executed in hardware (instead of JVM)
ARM assembly code is dense
C program code:
while (i != j)
{
if (i > j)
i -= j;
else
j -= i;
}
ARM assembly code:
loop CMP Ri, Rj
SUBGT Ri, Ri, Rj
SUBLT Rj, Rj, Ri
BNE loop
; set condition "NE" if (i != j)
; "GT" if (i > j), or "LT" if (i < j)
; if "GT", i = i-j
; if "LT", j = j-I
; if "NE", then loop
multiple pieces of work per instruction
ARM chip pricing
Core licensing – $200,000 to $10,000,000 depending
Some chip examples:
Atmel AT91SAM family -- $3/unit qty 10,000 (2005)
NXP LPC24xx family -- $8-14/unit qty 1 (2009)
Texas Instruments MS470 family - $10-22/unit qty 1 (2009)
For further pricing, check www.digikey.com
For further information, see www.arm.com