assembly - machine code template for immediate addressing -

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what machine code language immediate addressing..

if machine code template register adddressing is

opcode(6 bits) d(1 bit) w(1 bit) mod(2bits) reg(3bits) r/m(3bits)

total 16 bits.

m using intel 80386 intel microprocessor!

there few changes format immediate operands. (possibly always) high bit of opcode 1 instructions immediate operands. d bit replaced x (extension) bit. if operands 8-bit (w=0), x bit ignored. if operands not 8-bit , x=0, immediate value same size operand size. if x=1, immediate 8-bit number sign-extended current operand size. next, reg field replaced opcode extension, different depending on instruction in use. finally, immediate value added end of instruction, in little endian.

for more information see http://www.c-jump.com/cis77/cpu/x86/lecture.html, sections 21 , 37.


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