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#define _POSIX_C_SOURCE 200809L
//
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
#include <time.h>
#include <unistd.h>
// -- disable use of compiler intrinsics
// #define PU3_NO_INTRINSICS
// -- inaccurate clocks
// #define PU3_BAD_CLOCK
#ifndef PU3_BAD_CLOCK
clock_t ntime() {
struct timespec t;
clock_gettime(CLOCK_MONOTONIC_RAW, &t);
return t.tv_nsec + t.tv_sec * 1e9;
}
#else
clock_t ntime() {
struct timeval tv;
gettimeofday(&tv, NULL);
return tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
}
#endif
// it is time
// the thing you've none been waiting for
// pu3
typedef char *string;
typedef unsigned char byte;
typedef byte bool;
typedef struct {
byte __spare[ 1 ];
byte op;
uint16_t data;
uint32_t dest;
} pu3_inst_t;
typedef union {
pu3_inst_t inst_struct;
uint64_t inst_num;
} pu3_inst_u;
typedef struct {
pu3_inst_u *memory;
uint32_t mem_size;
uint32_t *pc;
uint32_t *time_slice;
} pu3_ctx;
// instructions
// 0: nop
// 1: halt
// 2: mov [target], src
pu3(pu3_ctx ctx) {
static uint32_t i;
static pu3_inst_t cur;
pu3_inst_u *pc = ctx.memory + *ctx.pc;
static const __attribute__((aligned(64))) void *GOTO_TABLE[] = {
&&inst_0,
&&pu3_end,
&&inst_2,
};
pu3_start:
cur = pc->inst_struct;
pc++;
#ifndef PU3_NO_INTRINSICS
__builtin_prefetch(pc + 1, 0, 3);
#endif
#define get_data() ((cur.op & 0b10000000) ? (ctx.memory[ cur.data ].inst_num) : (cur.data))
// 1 - 4: opcode
// 5: data_type [0 = constant, 1 = memory]
// [5] [ ] [ ] [ ] [1] [2] [3] [4]
goto *GOTO_TABLE[ cur.op & 0b1111 ];
inst_0: // nop
pc += cur.dest;
goto pu3_start;
inst_1: // halt
// unused, we just jump to break
inst_2: // mov
ctx.memory[ cur.dest ].inst_num = get_data();
goto pu3_start;
pu3_end:
*ctx.pc = pc - ctx.memory;
return *ctx.time_slice - i;
}
const string op_names[] = { "nop", "halt", "mov" };
// bench: measure using clock()
double bench_cycle(byte instr, pu3_ctx ctx) {
int i;
for (i = 16; i < ctx.mem_size; i++) {
ctx.memory[ i ].inst_struct.op = instr & 0b1111;
ctx.memory[ i ].inst_struct.dest = 5;
ctx.memory[ i ].inst_struct.data = 6;
if (i == ctx.mem_size - 1) ctx.memory[ i ].inst_struct.op = 1;
}
ctx.memory[ i ].inst_struct.op = 0;
*ctx.pc = 8;
clock_t start = ntime();
// int wstart = rdtsc();
pu3(ctx);
// int wend = rdtsc();
clock_t end = ntime();
double nanoseconds = (end - start);
double inst_count = *ctx.pc - 8;
double insts_per_ns = inst_count / nanoseconds;
double insts_per_s = insts_per_ns * 1e9;
printf(
"%-8s | time: %.3fms | insts: %.0f (%li real) | ips: %.3fM inst/s\n",
op_names[ instr ],
nanoseconds / 1000000,
inst_count,
end - start,
insts_per_ns * 1e3);
return insts_per_s / 1e6; // return M inst/s
}
main() {
static const uint32_t SIZE = 1 << 24;
pu3_ctx ctx = { .memory = calloc(SIZE, sizeof(pu3_inst_u)),
.mem_size = SIZE,
.pc = calloc(1, sizeof(uint32_t)),
.time_slice = calloc(1, sizeof(uint32_t)) };
bench_cycle(2, ctx);
}
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