
eZ8
™
CPU Core
User Manual
UM012820-0810 SUB Instruction
232
SUB
Definition
Subtract.
Syntax
SUB dst, src
Operation
dst
dst - src
Description
This instruction subtracts the source operand from the destination oper-
and. The destination operand stores the result. The source operand con-
tents are unaffected. The eZ8 CPU performs subtraction by adding the
two’s complement of the source operand to the destination operand.
Flags
C Set if a borrow is required by bit 7; reset otherwise
Z Set if the result is zero; reset otherwise
S Set if the result is negative; reset otherwise
V Set if an arithmetic overflow occurs; reset otherwise
D Set to 1
H Set if a borrow is required by bit 3; reset otherwise
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