GNU Info

(nasm.info)Section B.4.305

---

Next: Section B.4.306 Prev: Section B.4.304 Up: Section B.4

---

Enter node , (file) or (file)node

B.4.305. `SUB': Subtract Integers
---------------------------------

     SUB r/m8,reg8                 ; 28 /r                [8086]
     SUB r/m16,reg16               ; o16 29 /r            [8086]
     SUB r/m32,reg32               ; o32 29 /r            [386]

     SUB reg8,r/m8                 ; 2A /r                [8086]
     SUB reg16,r/m16               ; o16 2B /r            [8086]
     SUB reg32,r/m32               ; o32 2B /r            [386]

     SUB r/m8,imm8                 ; 80 /5 ib             [8086]
     SUB r/m16,imm16               ; o16 81 /5 iw         [8086]
     SUB r/m32,imm32               ; o32 81 /5 id         [386]

     SUB r/m16,imm8                ; o16 83 /5 ib         [8086]
     SUB r/m32,imm8                ; o32 83 /5 ib         [386]

     SUB AL,imm8                   ; 2C ib                [8086]
     SUB AX,imm16                  ; o16 2D iw            [8086]
     SUB EAX,imm32                 ; o32 2D id            [386]

   `SUB' performs integer subtraction: it subtracts its second operand
from its first, and leaves the result in its destination (first)
operand.  The flags are set according to the result of the operation:
in particular, the carry flag is affected and can be used by a
subsequent `SBB' instruction (*Note Section B.4.285::).

   In the forms with an 8-bit immediate second operand and a longer
first operand, the second operand is considered to be signed, and is
sign- extended to the length of the first operand. In these cases, the
`BYTE' qualifier is necessary to force NASM to generate this form of
the instruction.