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8227db3a23
This unifies VT_CMP with VT_JMP(i) by using mostly VT_CMP
with both a positive and a negative jump target list.
Such we can delay putting the non-inverted or inverted jump
until we can see which one is nore suitable (in most cases).
example:
if (a && b || c && d)
e = 0;
before this patch:
a: 8b 45 fc mov 0xfffffffc(%ebp),%eax
d: 83 f8 00 cmp $0x0,%eax
10: 0f 84 11 00 00 00 je 27 <main+0x27>
16: 8b 45 f8 mov 0xfffffff8(%ebp),%eax
19: 83 f8 00 cmp $0x0,%eax
1c: 0f 84 05 00 00 00 je 27 <main+0x27>
22: e9 22 00 00 00 jmp 49 <main+0x49>
27: 8b 45 f4 mov 0xfffffff4(%ebp),%eax
2a: 83 f8 00 cmp $0x0,%eax
2d: 0f 84 11 00 00 00 je 44 <main+0x44>
33: 8b 45 f0 mov 0xfffffff0(%ebp),%eax
36: 83 f8 00 cmp $0x0,%eax
39: 0f 84 05 00 00 00 je 44 <main+0x44>
3f: e9 05 00 00 00 jmp 49 <main+0x49>
44: e9 08 00 00 00 jmp 51 <main+0x51>
49: b8 00 00 00 00 mov $0x0,%eax
4e: 89 45 ec mov %eax,0xffffffec(%ebp)
51: ...
with this patch:
a: 8b 45 fc mov 0xfffffffc(%ebp),%eax
d: 83 f8 00 cmp $0x0,%eax
10: 0f 84 0c 00 00 00 je 22 <main+0x22>
16: 8b 45 f8 mov 0xfffffff8(%ebp),%eax
19: 83 f8 00 cmp $0x0,%eax
1c: 0f 85 18 00 00 00 jne 3a <main+0x3a>
22: 8b 45 f4 mov 0xfffffff4(%ebp),%eax
25: 83 f8 00 cmp $0x0,%eax
28: 0f 84 14 00 00 00 je 42 <main+0x42>
2e: 8b 45 f0 mov 0xfffffff0(%ebp),%eax
31: 83 f8 00 cmp $0x0,%eax
34: 0f 84 08 00 00 00 je 42 <main+0x42>
3a: b8 00 00 00 00 mov $0x0,%eax
3f: 89 45 ec mov %eax,0xffffffec(%ebp)
42: ...
Tiny C Compiler - C Scripting Everywhere - The Smallest ANSI C compiler ----------------------------------------------------------------------- Features: -------- - SMALL! You can compile and execute C code everywhere, for example on rescue disks. - FAST! tcc generates optimized x86 code. No byte code overhead. Compile, assemble and link about 7 times faster than 'gcc -O0'. - UNLIMITED! Any C dynamic library can be used directly. TCC is heading torward full ISOC99 compliance. TCC can of course compile itself. - SAFE! tcc includes an optional memory and bound checker. Bound checked code can be mixed freely with standard code. - Compile and execute C source directly. No linking or assembly necessary. Full C preprocessor included. - C script supported : just add '#!/usr/local/bin/tcc -run' at the first line of your C source, and execute it directly from the command line. Documentation: ------------- 1) Installation on a i386/x86_64/arm Linux/OSX/FreeBSD host ./configure make make test make install Notes: For OSX and FreeBSD, gmake should be used instead of make. For Windows read tcc-win32.txt. makeinfo must be installed to compile the doc. By default, tcc is installed in /usr/local/bin. ./configure --help shows configuration options. 2) Introduction We assume here that you know ANSI C. Look at the example ex1.c to know what the programs look like. The include file <tcclib.h> can be used if you want a small basic libc include support (especially useful for floppy disks). Of course, you can also use standard headers, although they are slower to compile. You can begin your C script with '#!/usr/local/bin/tcc -run' on the first line and set its execute bits (chmod a+x your_script). Then, you can launch the C code as a shell or perl script :-) The command line arguments are put in 'argc' and 'argv' of the main functions, as in ANSI C. 3) Examples ex1.c: simplest example (hello world). Can also be launched directly as a script: './ex1.c'. ex2.c: more complicated example: find a number with the four operations given a list of numbers (benchmark). ex3.c: compute fibonacci numbers (benchmark). ex4.c: more complicated: X11 program. Very complicated test in fact because standard headers are being used ! As for ex1.c, can also be launched directly as a script: './ex4.c'. ex5.c: 'hello world' with standard glibc headers. tcc.c: TCC can of course compile itself. Used to check the code generator. tcctest.c: auto test for TCC which tests many subtle possible bugs. Used when doing 'make test'. 4) Full Documentation Please read tcc-doc.html to have all the features of TCC. Additional information is available for the Windows port in tcc-win32.txt. License: ------- TCC is distributed under the GNU Lesser General Public License (see COPYING file). Fabrice Bellard.