REVE1 Logs

Endianness is the order in which the bytes of a multi-byte value are stored in memory: little-endian puts the least significant byte at the lowest address, big-endian the most significant. * Little-endian (x86) stores the least-significant byte at the lowest address; big-endian...

Quiz: REVE1 / The Processor Interface | updated: Jul 14, 2026

SAR fills the vacated upper bits with copies of the sign bit (preserving sign), while SHR fills them with zeros — so SAR is for signed values and SHR for unsigned. * Right-shift differs in the vacated top bit: sar copies the sign bit (correct for signed), shr shifts in a 0 (corr...

Quiz: REVE1 / The Processor Interface | updated: Jul 14, 2026

Programs are split into sections by content type so the OS can give each the right permissions — code read-only and executable, constants read-only, variables writable. * Each section gets the permissions it needs: code read-only and executable, constants read-only, globals writ...

Quiz: REVE1 / The Processor Interface | updated: Jul 14, 2026

Relocatable (.o), executable, and shared object (.so) — all three use the ELF format, differing mainly in how their addresses are represented. Type Extension Description Relocatable .o Compiled from one source file; contains code and data that can be combined with other .o...

Quiz: REVE1 / Program Execution | updated: Jul 14, 2026

.bss holds uninitialized (zero) globals and statics; it takes no space in the file — just a recorded size — and the loader zero-fills it in memory. * .data carries real bytes on disk; .bss carries only a size — the loader materialises its zeros in memory at startup. * // Goes in...

Quiz: REVE1 / Program Execution | updated: Jul 14, 2026

.text holds the executable code (functions and instructions); .data holds initialized global/static variables. * The main assembler sections: .text holds executable code, .data holds initialized read/write globals, and .rodata holds read-only constants. * An assembly file has no...

Quiz: REVE1 / Translation of C to Assembly | updated: Jul 14, 2026

cmp sets flags from a subtraction (S1 - S2); test sets flags from a bitwise AND (S1 & S2); neither stores the result — they only update the flags. Both are "throwaway-result" instructions: they perform an operation purely to set the condition flags, then discard the numeric answe...

Quiz: REVE1 / Translation of C to Assembly | updated: Jul 14, 2026

x/NFU address — examine N items, in Format (x=hex, d=dec, i=instruction, s=string…), of Unit size (b/h/w/g = 1/2/4/8 bytes) — starting at address. GDB's x is the Swiss-army knife for inspecting raw memory while reverse-engineering. The count, format, and unit are bundled into one...

Quiz: REVE1 / Translation of C to Assembly | updated: Jul 14, 2026

Assembly is a human-readable, essentially one-to-one notation for machine code — each assembly instruction maps to one binary machine instruction. Machine code is just bytes; assembly is those same bytes written with names. The mapping is direct: add %rbx, %rax → 48 01 d8 mov...

Quiz: REVE1 / The Processor Interface | updated: Jul 14, 2026

They modify one operand in place: inc (+1), dec (−1), neg (two's-complement negate), and not (bitwise complement). These are compact, common operations on a single value: Instruction Effect inc D D ← D + 1 dec D D ← D − 1 neg D D ← −D (two's complement) not D D ← ~D...

Quiz: REVE1 / The Processor Interface | updated: Jul 14, 2026