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author | Andrew Waterman <waterman@cs.berkeley.edu> | 2014-11-25 13:39:53 -0800 |
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committer | Andrew Waterman <waterman@cs.berkeley.edu> | 2014-11-25 14:40:51 -0800 |
commit | 590417bec978bfc3fbf35d303760494395eb65b2 (patch) | |
tree | e264e60f8ad9eba772257c9b2676997cd02b7140 /dummy_rocc | |
parent | c31742961bdab9094c35ef6c1b33186892aa34d1 (diff) | |
download | riscv-isa-sim-590417bec978bfc3fbf35d303760494395eb65b2.zip riscv-isa-sim-590417bec978bfc3fbf35d303760494395eb65b2.tar.gz riscv-isa-sim-590417bec978bfc3fbf35d303760494395eb65b2.tar.bz2 |
Factor out the dummy RoCC accelerator
Diffstat (limited to 'dummy_rocc')
-rw-r--r-- | dummy_rocc/dummy_rocc.ac | 0 | ||||
-rw-r--r-- | dummy_rocc/dummy_rocc.cc | 47 | ||||
-rw-r--r-- | dummy_rocc/dummy_rocc.mk.in | 7 | ||||
-rw-r--r-- | dummy_rocc/dummy_rocc_test.c | 29 |
4 files changed, 83 insertions, 0 deletions
diff --git a/dummy_rocc/dummy_rocc.ac b/dummy_rocc/dummy_rocc.ac new file mode 100644 index 0000000..e69de29 --- /dev/null +++ b/dummy_rocc/dummy_rocc.ac diff --git a/dummy_rocc/dummy_rocc.cc b/dummy_rocc/dummy_rocc.cc new file mode 100644 index 0000000..85ab7aa --- /dev/null +++ b/dummy_rocc/dummy_rocc.cc @@ -0,0 +1,47 @@ +#include "rocc.h" +#include "mmu.h" +#include <cstring> + +class dummy_rocc_t : public rocc_t +{ + public: + const char* name() { return "dummy_rocc"; } + + reg_t custom0(rocc_insn_t insn, reg_t xs1, reg_t xs2) + { + reg_t prev_acc = acc[insn.rs2]; + + if (insn.rs2 >= num_acc) + illegal_instruction(); + + switch (insn.funct) + { + case 0: // acc <- xs1 + acc[insn.rs2] = xs1; + break; + case 1: // xd <- acc (the only real work is the return statement below) + break; + case 2: // acc[rs2] <- Mem[xs1] + acc[insn.rs2] = p->get_mmu()->load_uint64(xs1); + break; + case 3: // acc[rs2] <- accX + xs1 + acc[insn.rs2] += xs1; + break; + default: + illegal_instruction(); + } + + return prev_acc; // in all cases, xd <- previous value of acc[rs2] + } + + dummy_rocc_t() + { + memset(acc, 0, sizeof(acc)); + } + + private: + static const int num_acc = 4; + reg_t acc[num_acc]; +}; + +REGISTER_EXTENSION(dummy_rocc, []() { return new dummy_rocc_t; }) diff --git a/dummy_rocc/dummy_rocc.mk.in b/dummy_rocc/dummy_rocc.mk.in new file mode 100644 index 0000000..298b9f9 --- /dev/null +++ b/dummy_rocc/dummy_rocc.mk.in @@ -0,0 +1,7 @@ +dummy_rocc_subproject_deps = \ + spike \ + riscv \ + softfloat \ + +dummy_rocc_srcs = \ + dummy_rocc.cc \ diff --git a/dummy_rocc/dummy_rocc_test.c b/dummy_rocc/dummy_rocc_test.c new file mode 100644 index 0000000..94de8c0 --- /dev/null +++ b/dummy_rocc/dummy_rocc_test.c @@ -0,0 +1,29 @@ +// The following is a RISC-V program to test the functionality of the +// dummy RoCC accelerator. +// Compile with riscv64-unknown-elf-gcc dummy_rocc_test.c +// Run with spike --extension=dummy_rocc pk a.out + +#include <assert.h> +#include <stdio.h> +#include <stdint.h> + +int main() { + uint64_t x = 123, y = 456, z = 0; + // load x into accumulator 2 (funct=0) + asm volatile ("custom0 x0, %0, 2, 0" : : "r"(x)); + // read it back into z (funct=1) to verify it + asm volatile ("custom0 %0, x0, 2, 1" : "=r"(z)); + assert(z == x); + // accumulate 456 into it (funct=3) + asm volatile ("custom0 x0, %0, 2, 3" : : "r"(y)); + // verify it + asm volatile ("custom0 %0, x0, 2, 1" : "=r"(z)); + assert(z == x+y); + // do it all again, but initialize acc2 via memory this time (funct=2) + asm volatile ("custom0 x0, %0, 2, 2" : : "r"(&x)); + asm volatile ("custom0 x0, %0, 2, 3" : : "r"(y)); + asm volatile ("custom0 %0, x0, 2, 1" : "=r"(z)); + assert(z == x+y); + + printf("success!\n"); +} |