| author | Christian Urban <christian.urban@kcl.ac.uk> |
| Mon, 27 Jul 2020 01:55:05 +0100 | |
| changeset 740 | 923b946347e6 |
| parent 738 | progs/bf/bfc0.scala@084e2843f478 |
| child 742 | b5b5583a3a08 |
| permissions | -rw-r--r-- |
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738
084e2843f478
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
736
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// A Transpiler for the Brainf*** language to C |
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084e2843f478
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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//=============================================== |
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084e2843f478
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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// |
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084e2843f478
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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// Call with |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
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// |
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084e2843f478
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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// amm bfc0.sc <<bf_program.bf>> |
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084e2843f478
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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diff
changeset
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// |
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// |
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// Note: An interesting exercise is to call |
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// gcc with -O3 instead of -O0 |
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// simple instructions |
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def instr(c: Char) : String = c match {
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case '>' => "ptr++;" |
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case '<' => "ptr--;" |
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case '+' => "(*ptr)++;" |
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case '-' => "(*ptr)--;" |
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case '.' => "putchar(*ptr);" |
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case ',' => "*ptr = getchar();" |
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case '[' => "while(*ptr){"
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case ']' => "}" |
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case _ => "" |
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} |
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def instrs(prog: String) : String = |
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prog.toList.map(instr(_)).mkString |
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// adding the boilerplate |
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def compile(prog: String) : String = |
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s"""#include <string.h> |
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#include <stdio.h> |
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char field[30000]; |
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char *ptr = &field[15000]; |
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int main() {
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memset(field, '\\0', 30000); |
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${instrs(prog)}
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return 0;}""" |
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def compile_file(name: String, prog: String) = |
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os.write.over(os.pwd / name, compile(prog)) |
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// running the c-compiler over the transpiled |
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// BF program and running the resulting binary |
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def compile_run(prog: String) = {
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val tn = "tmp" |
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compile_file(s"${tn}.c", prog)
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os.proc("gcc", "-O0", "-o", tn, s"${tn}.c").call() // call gcc
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os.proc("./tmp").call(stdout = os.Inherit) // run binary
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} |
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// Running Testcases |
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//=================== |
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def time_needed[T](n: Int, code: => T) = {
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val start = System.nanoTime() |
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for (i <- 0 until n) code |
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val end = System.nanoTime() |
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(end - start)/(n * 1.0e9) |
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} |
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738
084e2843f478
updated
Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
736
diff
changeset
|
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@doc(" the argument should be a BF program ")
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084e2843f478
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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changeset
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@main |
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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def main(fname: String) = {
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084e2843f478
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
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diff
changeset
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val bf_str = os.read(os.pwd / fname) |
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println(s"${time_needed(1, compile_run(bf_str))} secs")
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084e2843f478
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Christian Urban <christian dot urban at kcl dot ac dot uk>
parents:
736
diff
changeset
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} |
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