Intel 8253 - Page 557

4/17/98 6-157 Addressing Modes and Data Types
SUB Rd, [Rs+]
Bytes: 2
Clocks: 5
Operation: (Rd) <-- (Rd) - ((WS:Rs))
(Rs) <-- (Rs) + 1 (byte operation) or 2 (word operation)
Encoding:
SUB [Rd+], Rs
Bytes: 2
Clocks: 5
Operation: ((WS:Rd)) <-- ((WS:Rd)) - (Rs)
(Rd) <-- (Rd) + 1 (byte operation) or 2 (word operation)
Encoding:
SUB direct, Rs
Bytes: 3
Clocks: 4
Operation: (direct) <-- (direct) - (Rs)
Encoding:
byte 3: lower 8 bits of direct
SUB Rd, direct
Bytes: 3
Clocks: 4
Operation: (Rd) <-- (Rd) - (direct)
Encoding:
byte 3: lower 8 bits of direct
0 0 1 0 SZ 0 1 1 d d d d 0 s s s
0 0 1 0 SZ 0 1 1 s s s s 1 d d d
0 0 1 0 SZ 1 1 0 s s s s 1 direct: 3 bits
0 0 1 0 SZ 1 1 0 d d d d 0 direct: 3 bits