User's Manual

BASIC INSTRUCTION SET
HIGH ADDRESS ..
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OPERANDS FROM ~n\\\\\\n\\l\~\\\\\\\
PREVIOUS PUSH
INSTRUCTIONS ~\\\\\\\\\\\\\\\\\\\\\\\\
SP_ OPERAND
LOW ADDRESS
Ok
BEFORE
POP OPERAND
AFTER
POP OPERAND
SS
,
POP copies the contents of the slsck location before SP to the operand In the Instruction. POP then Increments SP by 2 bytes
(1 word).
G3010e
Figure 3-3. POP
3.2 FLAG OPERATION WITH THE BASIC INSTRUCTION SET
3.2.1 Status Flags
The status flags of the FLAGS register reflect conditions that result from a previous instruction or
instructions. The arithmetic instructions use
OF, SF, ZF, AF, PF, and CF.
The
SCAS (Scan String), CMPS (Compare String), and LOOP instructions use ZF to signal that their
operations are complete. The base architecture includes instructions
to set, clear, and complement CF
before execution of an arithmetic instruction. See figure 3-5 and tables 3-1 and 3-2.
3.2.2 Control Flags
The control flags of the FLAGS register determine processor operations for string instructions, maska-
ble interrupts, and debugging.
3-4