Slashdot Mirror
GCC 4.8.0 Release Marks Completion of C++ Migration
hypnosec writes "GCC 4.8.0 has been released (download), and with it, the developers of the GNU Compiler Collection have switched to C++ as the implementation language, a project the developers have been working for years. Licensed under the GPLv3 or later, version 4.8.0 of the GCC not only brings with it performance improvements but also adds memory error detector AddressSanitizer, and race condition detection tool the ThreadSanitizer. Developers wanting to build their own version of GCC should have at their disposal a C++ compiler that understands C++ 2003."
How was the first compiler compiled?
With an assembler. (of course, real men didn't need an assembler, they toggled in the hexadecimal opcodes directly in hex, using a hickory switch and a quart of whiskey)
I don't care if it's 90,000 hectares. That lake was not my doing.
You need to compile this compiler with a compiler which begs the question....
Sigh. It raises the question. To "beg the question" means something completely different. Here is a simple rule of thumb of when that phrase should be used: never.
How was the first compiler compiled?
The first compilers (Fortran and Lisp) were written in assembler. Later compilers were written in Lisp or Fortran.
New languages can be bootstrapped by first implementing a sufficient subset, and then expanding it. Ken Thompson explains this process (and how to subvert the process) in his Turing Award lecture on Trusting Trust.
Enough people use the term "beg the question" this way that I've just gotten used to it by now. It doesn't bother me anymore. It's over, man. The war is lost. It's in common use now. Rewire the part of your brain that gets annoyed by it. You will be happier in the long run.
From the changelog: "A new general optimization level, -Og, has been introduced. It addresses the need for fast compilation and a superior debugging experience while providing a reasonable level of runtime performance. Overall experience for development should be better than the default optimization level -O0."
This actually sounds really attractive to me... I'll have to try it out.
Hexadecimal? You kids and your newfangled contraptions. Back in my day, we had to use BINARY, and we were always running out of 1's so we had to take the 0's to the blacksmith and have them cut down and straightened before we could use them.
I remember seeing a pretty cool 8080 program to zero memory. It went something like:
LXI BC, 0000
LXI HL, 0009
LXI SP, 0008
PUSH BC
PCHL
HL, BC, and SP (the stack pointer) are all 16-bit registers, and the first three instructions occupy 0x0000-0x0008 in memory. PUSH BC is one byte at 0x0009, and PCHL (another one-byte instruction) sets the program counter to the value of HL; essentially it allows you to jump to the address contained in the HL register. The PUSH operation decremented the stack pointer before storing each of the bytes, so you would set the stack pointer to one higher than the highest address you wanted to overwrite. Because the 8080 was little-endian, address 0x0008 was the upper byte of the third instruction's numeric value - it was already zero (if it were big-endian you could just throw in a NOP to get it to align properly). The final PUSH operation - after the program had cycled through all of memory - wiped out the PUSH BC and PCHL operations, and the computer would go to all NOPs.