The LEON4 processor core is a synthesizable VHDL model of a 32-bit processor compliant with the SPARC V8 architecture. The core is highly configurable and particularly suitable for high performance multi-core system-on-a-chip (SOC) designs.
The core is interfaced using the AMBA 2.0 AHB bus and supports the IP core plug&play method provided in the Aeroflex Gaisler IP library (GRLIB). The processor can be efficiently implemented on FPGA and ASIC technologies and uses standard synchronous memory cells for caches and register file. The processor supports the MUL, MAC and DIV instructions and an optional IEEE- 754 floating-point unit (FPU) and Memory Management Unit (MMU). The LEON4 cache system consists of separate I/D multi-set Level-1 (L1) caches with up to 4 ways per cache, and an optional Level-2 (L2) cache for increased performance in data intensive applications. The LEON4 pipeline uses 64-bit internal load/store data paths, with an AMBA AHB interface of either 64- or 128-bit. Branch prediction, 1-cycle load latency and a 32x32 multiplier results in a performance of 1.7 DMIPS/MHz, or 2.1 Coremark/MHz.
The wider interfaces provides higher bus and memory bandwidth which is necessary when designing ASICs with high clock frequencies (800 MHz and above). The LEON4 is fully software compatible with previous LEON processors. The configurability of LEON4 allows designers to optimize the processor for performance, power consumption, I/O throughput, silicon area and cost.