Loongson
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Loongson 2E
Loongson 2E was designed by ICT (Institute of Computing Technology), a department of The Chinese Academy of Sciences, helped and manufactured by STMicroelectronics.
ST Generic Part Number: STLS2E02
Features
Microarchitecture:
- 64 bit
- 9 pipeline stages
- 4-issue Out-Of-Order Executive
- 2 ALU, 2 FALU, 1 SIMD, 1 Load/Store Units
ISA: MIPS III
Cache: 64KB L1 data, 64KB L1 instruction, on-chip 512KB L2.
Clock Frequency: 600MHz - 800MHz.
TDP: 4 Watt at 700MHz
Integrated: DDR-333 memory controller.
Highlights
- ST's Leading Edge 90nm process.
- Some new instructions: Allow write to register directly without MFLO or MFHI.
- Some new instructions: MADD.[S|D] MSUB.[S|D] NMADD.[S|D] NMSUB.[S|D].
- Some new SIMD instructions: similar to MMX, using FPU for parallel fixed-point arithmetic.
- An Execution bit: help OS to protect from buffer-flow attack.
Devices based on this CPU
Processor documentation
Chinese version
English version
Loongson 2F
Loongson 2F is the latest processor in Loongson 2 Family. Also manufactured by STMicroelectronics.
It is identical to the Loongson 2E with several improvements:
- Higher Clock Frequency: 1.2GHz maximum
- Advanced power control technology: less than 6 Watt under 1GHz in the same 90nm
- Integrated DDR2 controller
- Integrated northbridge providing faster IO (compared with former PCI bus) with PCI-X 66 bus
- Smaller Packaging.
Devices based on this CPU
Processor documentation
Chinese version
English version
Appearance to Operating System
The following shows the contents of /proc/cpuinfo using Linux kernel 2.6.35
$ cat /proc/cpuinfo system type : lemote-fuloong-2f-box processor : 0 cpu model : ICT Loongson-2 V0.3 FPU V0.1 BogoMIPS : 530.43 wait instruction : no microsecond timers : yes tlb_entries : 64 extra interrupt vector : no hardware watchpoint : yes, count: 0, address/irw mask: [] ASEs implemented : shadow register sets : 1 core : 0 VCED exceptions : not available VCEI exceptions : not available
Optimizing GNU/Linux distributions for Loongson 2F
Loongson2f software works considerably faster if compiled with the correct flags. Also, some flags are required to work around processor bugs early in the production runs.
- Linux on Loongson Community hosted at Lemote.
Discussion Threads
- Current loongson2f linux version / compiler / version flags wisdom?
- Taking full advantage of MIPSEL / loongson2f CPU
