ELVMのCバックエンド・constexprバックエンドの出力例

0_regjmp.eir

# 出典: https://github.com/shinh/elvm/blob/master/test/05regjmp.eir
mov A, l
jmp A
putc 78
exit
l:
putc 89
exit

1_regjmp.c

// ELVM Cバックエンドの出力

#include <stdio.h>
#include <stdlib.h>
// レジスタとメモリをグローバル変数として用意
unsigned int a;
unsigned int b;
unsigned int c;
unsigned int d;
unsigned int bp;
unsigned int sp;
unsigned int pc;
unsigned int mem[1<<24];

void func0() {
 while (0 <= pc && pc < 512) { 
  switch (pc) {　//プログラムカウンタの値によって、switch
  case -1:  /* dummy */
   break;

  case 0:
   if (1) pc = 1 - 1;
   break;

  case 1:
   a = 3;
   if (1) pc = a - 1;
   break;

  case 2:
   putchar(78);
   exit(0);
   break;

  case 3:
   putchar(89);
   exit(0);
  }
  pc++;
 }
}
int main() {
 mem[0] = 1;

 while (1) {
  switch (pc / 512 | 0) {
  case 0:
   func0();
   break;
  }
 }
 return 1;
}

2_regjmp.cpp

// ELVM C++ constexprバックエンドの出力

#include <cstdio>
#include <utility>

const size_t BUF_SIZE = 10000;

constexpr char input[] =
#include "input.txt"
;

struct buffer {
 unsigned int size;
 unsigned int b[BUF_SIZE];
};
template <size_t... I>
constexpr buffer make_buf_impl(unsigned int size, unsigned int* buf, std::index_sequence<I...>) {
 return buffer{size, {buf[I]...}};
}
constexpr buffer make_buf(unsigned int size, unsigned int* buf) {
 return make_buf_impl(size, buf, std::make_index_sequence<BUF_SIZE>{});
}

constexpr buffer constexpr_main() {
 unsigned int a = 0;
 unsigned int b = 0;
 unsigned int c = 0;
 unsigned int d = 0;
 unsigned int bp = 0;
 unsigned int sp = 0;
 unsigned int pc = 0;
 unsigned int i_cur = 0;
 unsigned int o_cur = 0;
 unsigned int mem[1<<24] = {0};
 unsigned int buf[BUF_SIZE] = {0};
 mem[0] = 1;

 while (1) {
  switch (pc) {
  case 0:
   if (1) pc = 1 - 1;
   break;

  case 1:
   a = 3;
   if (1) pc = a - 1;
   break;

  case 2:
   buf[o_cur++] = 78;
   return make_buf(o_cur, buf);
   break;

  case 3:
   buf[o_cur++] = 89;
   return make_buf(o_cur, buf);
  }
  pc++;
 }
 return make_buf(o_cur, buf);
}

int main() {
 constexpr buffer buf = constexpr_main();
 constexpr unsigned int output_size = buf.size;

 for(int i = 0; i < output_size; ++i) {
  putchar(buf.b[i]);
 }
}