IBM 5150 Hardware Reference Manual page 290

CLD = Clear direction S1D = Set direction
1111111001 111 111 1 0
C II
=
Clear interrupt
S11 = Set interrupt
1111110101 1 1 1 1 1 1 0 1 1
HL1= Halt WAI1 = Wait
1 1 1 1 0 1 0 0 1
1 0 0 1 1 0 1 1
LOCK
=
Bus lock prefix ESC
=
Escape (to external device)
1 1 1 1 0 0 0 0 \
1 1 0 1 1 x x x
I
mod x x x
rIm
Footnotes:
if d
=
1 then "to"; if d
=
0 then "from"
if w
=
1 then word instruction; if w
=
0 then byte instruction
if s:w = 01 then 16 bits of immediate data from the operand
if s:w = 11 then an immediate data byte is sign extended to form the
16·bit operand
ifv
=
0 then "count" = 1; if v
=
1 then "count" in (C
Ll
x
=
don't care
~
z is used for some string primitives to compare with ZF FLAG
AL
=
8·bit accumulator
AX
=
16-bit accumulator
CX = Count register
DS = Data segment
DX
=
Variable port register
ES
=
Extra segment
Above/below refers to unsigned value
Greater = more positive;
Less
=
less positive (more negative) signed values
B-lS