iBurg

Grandpa code generator-generator in LCC

Linker Scripts VMA vs LMA

VMA is virtual memory address while LMA is load memory address. If both are not equal, which one of the addresses does linker consider while resolving symbols' addresses?

Let us consider a simple program test.c:

int i=10;
int main() {
return i++;
}

After compiling it to ELF-executable, dump the output sections. (I am compiling for AVR target using avr-gcc)

Sections:
Idx Name          Size      VMA       LMA       File off  Algn
  0 .text         00000040  00000000  00000000  00000074  2**1
                    CONTENTS, ALLOC, LOAD, READONLY, CODE
  1 .data         00000002  00800060  00000040  000000b4  2**0
                     CONTENTS, ALLOC, LOAD, DATA

Notice the values in bold. VMA and LMA of .data section differ? Since 'i' is the only variable, what address will 'i' have? VMA or LMA ? When the text section is disassembled, what will be the address of memory accessed by instructions to read and write the value of variable 'i'?


Reference for linker script file:  Linker Script Documentation

Relocations - I

Link-Time/Load-Time/Run-Time Relocations vs Software and Hardware Relocations vs Linkers and Loaders.

I am in a zombie state.

The case for Reduced Instruction Set Computer

This wonderful newsletter in SIGARCH(1980) by Patterson et.al explains the origins of RISC architectures in much simpler terms.



Particularly sections- 'irrational implementations' and 'Supporting HLLCS' accompanied by footnotes laid a strong case even though (I admit that) the argument against CISC seems a little incomplete without sound proof but then it is just a newsletter. Wish I read it 3 years ago :-(

Reference: http://portal.acm.org/citation.cfm?doid=641914.641917

Whole Program Analysis (WHOPR)

Google is after link time optimization - in big leaps.

Reference: http://gcc.gnu.org/projects/lto/whopr.pdf

Kleene-Rosser Paradox

I wish I can understand what exactly is paradoxical in this...

What if a function negates itself? However much I try I am simply unable to do away with my C-language perspective.

An alternate solution is to re-interpret lambda calculus not as a theory of logical assertions, but rather as a means of expressing computation. In this way, the paradox can be "solved" by reinterpreting it as a recursive statement, that is, the infinite recursion implying

Time to realize that functional languages very much exist.

Evolution of Compilers

Citation : Evolution of Compilers, Priti Shankar, Resonance, August 2007.