Assembly Language for Beginners

1.24. STRUCTURES

push esi

lea esi, DWORD PTR _b$[esp+24]

mov DWORD PTR [esi], eax

mov DWORD PTR [esi+4], ebx

mov DWORD PTR [esi+8], ecx

mov DWORD PTR [esi+12], edx

mov esi, DWORD PTR _b$[esp+24]

mov eax, esi

and eax, 15

push eax

push OFFSET $SG15435 ; 'stepping=%d', 0aH, 00H

call _printf

mov ecx, esi

shr ecx, 4

and ecx, 15

push ecx

push OFFSET $SG15436 ; 'model=%d', 0aH, 00H

call _printf

mov edx, esi

shr edx, 8

and edx, 15

push edx

push OFFSET $SG15437 ; 'family_id=%d', 0aH, 00H

call _printf

mov eax, esi

shr eax, 12

and eax, 3

push eax

push OFFSET $SG15438 ; 'processor_type=%d', 0aH, 00H

call _printf

mov ecx, esi

shr ecx, 16

and ecx, 15

push ecx

push OFFSET $SG15439 ; 'extended_model_id=%d', 0aH, 00H

call _printf

shr esi, 20

and esi, 255

push esi

push OFFSET $SG15440 ; 'extended_family_id=%d', 0aH, 00H

call _printf

add esp, 48

pop esi

xor eax, eax

pop ebx

add esp, 16
ret 0
_main ENDP

TheSHRinstruction shifting the value inEAXby the number of bits that must beskipped, e.g., we ignore
some bitsat the right side.

TheANDinstruction clears the unneeded bitson the left, or, in other words, leaves only those bits in the
EAXregister we need.