Intel 80C186EA, User Manual

Page: 342 / 417

C-7
INSTRUCTION SET DESCRIPTIONS
BOUND Detect Value Out of Range:
BOUND dest, src
Provides array bounds checking in
hardware. The calculated array index
is placed in one of the general purpose
registers, and the upper and lower
bounds of the array are placed in two
consecutive memory locations. The
contents of the register are compared
with the memory location values, and if
the register value is less than the first
location or greater than the second
memory location, a trap type 5 is
generated.
Instruction Operands:
BOUND reg, mem
if
((dest) < (src) or (dest) > ((src) + 2)
then
(SP)
←
(SP) – 2
((SP) + 1 : (SP))
←
FLAGS
(IF)
←
0
(TF)
←
0
(SP)
←
(SP) – 2
((SP) + 1 : (SP))
←
(CS)
(CS)
←
(1EH)
(SP)
←
(SP) – 2
((SP) + 1 : (SP))
←
(IP)
(IP)
←
(1CH)
AF –
CF –
DF –
IF –
OF –
PF –
SF –
TF –
ZF –
CALL Call Procedure:
CALL procedure-name
Activates an out-of-line procedure,
saving information on the stack to
permit a RET (return) instruction in the
procedure to transfer control back to
the instruction following the CALL. The
assembler generates a different type
of CALL instruction depending on
whether the programmer has defined
the procedure name as NEAR or FAR.
Instruction Operands:
CALL near-proc
CALL far-proc
CALL memptr16
CALL regptr16
CALL memptr32
if
Inter-segment
then
(SP)
←
(SP) – 2
((SP) +1:(SP))
←
(CS)
(CS)
←
SEG
(SP)
←
(SP) – 2
((SP) +1:(SP))
←
(IP)
(IP)
←
dest
AF –
CF –
DF –
IF –
OF –
PF –
SF –
TF –
ZF –
Table C-4. Instruction Set (Continued)
Name Description Operation
Flags
Affected
NOTE: The three symbols used in the Flags Affected column are defined as follows:
– the contents of the flag remain unchanged after the instruction is executed
? the contents of the flag is undefined after the instruction is executed
ü
the flag is updated after the instruction is executed