It also depends on instruction mix. Your processor will have several computation units standing by at any time, and you’ll get maximum throughput if all of them are filled all the time. So, executing a loop of mul’s is just as fast as executing a loop or adds – but the same doesn’t hold if … Read more
In Unix/Linux systems: .a is the usual extension for static libraries (aka Archives of multiple .o files, made with ar(1)). Dynamic libraries, aka Shared Objects, use .so. .s is used for asm compiler output. (gcc -S foo.c produces asm output, with a default filename of foo.s) .S is used for hand-written asm source files. gcc … Read more
(In the diagrams and text below, PC is the address of the branch instruction itself. PC+4 is the end of the branch instruction itself, and the start of the branch delay slot. Except in the absolute jump diagram.) 1. Branch Address Calculation In MIPS branch instruction has only 16 bits offset to determine next instruction. … Read more
The move instruction copies a value from one register to another. The li instruction loads a specific numeric value into that register. For the specific case of zero, you can use either the constant zero or the zero register to get that: move $s0, $zero li $s0, 0 There’s no register that generates a value … Read more
There is no difference between the temporary and saved variables in how they work. The difference is in how they are used, or rather, how they ought to be used. The MIPS calling convention specifies how the various registers are to be used — the $v registers are for function returns, the $a registers are … Read more
Branches allow for conditions. But allowing for conditions takes up more bits in the instruction. Therefore, a branch’s address is only 2^16 bits and only allows you to branch 2^15 – 1 instructions backward or 2^15 instructions forward. A jump is unconditional and the bits saved by leaving out the condition can be used for … Read more
What is it? It is an emulator image that emulates a device that has a MIPS CPU, instead of an ARM or x86 CPU. What does it do and when will someone use it? You will use it if you wish to emulate a device that has a MIPS CPU, instead of an ARM or … Read more
CMake tries to compile an executable using “standard” (as per what CMake thinks is standard) compiler options and tries to run that executable, so to see if the compiler is working. The executable is simple like int main(int argc, char *argv[]) { return argc – 1; }. You can’t do that when cross-compiling. Because usually … Read more
Couple of possible reasons for it: x86 is a relatively old ISA (its progenitors were 8086s, after all) x86 has evolved significantly several times, but hardware is required to maintain backwards compatibility with old binaries. For example, modern x86 hardware still contains support for running 16 bit code natively. Additionally, several memory-addressing models exist to … Read more
You’re missing the 32 bit libc dev package: On Ubuntu it’s called libc6-dev-i386 – do sudo apt-get install libc6-dev-i386. See below for extra instructions for Ubuntu 12.04. On Red Hat distros, the package name is glibc-devel.i686 (Thanks to David Gardner’s comment). On CentOS 5.8, the package name is glibc-devel.i386 (Thanks to JimKleck’s comment). On CentOS … Read more