Re:Revisiting 64-bit-ness in Visual Studio and elsewhere (2015)
by wolfgke on Friday March 10, 2017 @10:24AM
(#13839237)
> No. With 8 bit you had to execute multiple instructions to add two numbers. Same with 16 bit.
Wrong (for x86-16 vs. x86-32). Just use an operand-size size override prefix (0x66) with your 16 bit real mode ALU (in this case 'add') instruction to make it a 32 bit ALU instruction. Works from 80386 on, where the 32 bit registers were introduced.
Wrong (for x86-16 vs. x86-32). Just use an operand-size size override prefix (0x66) with your 16 bit real mode ALU (in this case 'add') instruction to make it a 32 bit ALU instruction. Works from 80386 on, where the 32 bit registers were introduced.