mirror of https://git.tukaani.org/xz.git
66 lines
1.3 KiB
C
66 lines
1.3 KiB
C
///////////////////////////////////////////////////////////////////////////////
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//
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/// \file bcj_test.c
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/// \brief Source code of compress_prepared_bcj_*
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///
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/// This is a simple program that should make the compiler to generate
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/// PC-relative branches, jumps, and calls. The compiled files can then
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/// be used to test the branch conversion filters. Note that this program
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/// itself does nothing useful.
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///
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/// Compiling: gcc -std=c99 -fPIC -c bcj_test.c
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/// Don't optimize or strip.
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//
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// Author: Lasse Collin
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//
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// This file has been put into the public domain.
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// You can do whatever you want with this file.
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//
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///////////////////////////////////////////////////////////////////////////////
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extern int jump(int a, int b);
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extern int
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call(int a, int b)
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{
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if (a < b)
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a = jump(a, b);
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return a;
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}
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extern int
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jump(int a, int b)
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{
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// The loop generates conditional jump backwards.
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while (1) {
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if (a < b) {
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a *= 2;
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a += 3 * b;
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break;
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} else {
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// Put enough code here to prevent JMP SHORT on x86.
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a += b;
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a /= 2;
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b += b % 5;
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a -= b / 3;
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b = 2 * b + a - 1;
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a *= b + a + 1;
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b += a - 1;
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a += b * 2 - a / 5;
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}
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}
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return a;
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}
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int
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main(int argc, char **argv)
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{
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int a = call(argc, argc + 1);
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return a == 0;
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}
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