One interesting aspect of a computer’s instruction set is its addressing modes, how the computer determines the address for a memory access. The Intel 8086 (1978) used the ModR/M byte, a special byte following the opcode, to select the addressing mode. The ModR/M byte has persisted into the modern x86 architecture, so it’s interesting to look at its roots and original imple ... ⌘ Read more
One interesting aspect of a computer’s instruction set is its addressing modes, how the computer determines the address for a memory access. The Intel 8086 (1978) used the ModR/M byte, a special byte following the opcode, to select the addressing mode. The ModR/M byte has persisted into the modern x86 architecture, so it’s interesting to look at its roots and original imple ... ⌘ Read more