xref: /openbmc/u-boot/doc/README.AX25 (revision e11ef3d2)
1AX25 is Andes CPU IP to adopt RISC-V architecture.
2
3Features
4========
5
6CPU Core
7 - 5-stage in-order execution pipeline
8 - Hardware Multiplier
9	 - radix-2/radix-4/radix-16/radix-256/fast
10 - Hardware Divider
11 - Optional branch prediction
12 - Machine mode and optional user mode
13 - Optional performance monitoring
14
15ISA
16 - RV64I base integer instructions
17 - RVC for 16-bit compressed instructions
18 - RVM for multiplication and division instructions
19
20Memory subsystem
21 - I & D local memory
22   - Size: 4KB to 16MB
23 - Memory subsyetem soft-error protection
24   - Protection scheme: parity-checking or error-checking-and-correction (ECC)
25   - Automatic hardware error correction
26
27Bus
28 - Interface Protocol
29   - Synchronous AHB (32-bit/64-bit data-width), or
30   - Synchronous AXI4 (64-bit data-width)
31
32Power management
33 - Wait for interrupt (WFI) mode
34
35Debug
36 - Configurable number of breakpoints: 2/4/8
37 - External Debug Module
38   - AHB slave port
39 - External JTAG debug transport module
40
41Platform Level Interrupt Controller (PLIC)
42 - AHB slave port
43 - Configurable number of interrupts: 1-1023
44 - Configurable number of interrupt priorities: 3/7/15/63/127/255
45 - Configurable number of targets:  1-16
46 - Preempted interrupt priority stack
47