ZiLOG Z80380 User Manual page 208

Z
ILOG
SUB
SUBTRACT FROM STACK POINTER (WORD)
SUB SP,src
Operation: if (XM) then begin
SP(31-0)
end
else begin
SP(15-0)
end
The source operand is subtracted from the SP register and the difference is stored in the SP
register. This has the effect of allocating or deallocating space on the stack. Two's
complement subtraction is performed.
Flags: S: Unaffected
Z: Unaffected
H: Set if there is a borrow from bit 12 of the result; cleared otherwise
V: Unaffected
N: Set
C: Set if there is a borrow from the most significant bit of the result; cleared otherwise
Addressing
Mode Syntax
IM: SUB SP,nn
5-174
src = IM
←
SP(31-0) – src(31-0)
←
SP(15-0) – src(15-0)
Instruction Format
11101101 10010010 -n(low)- -n(high)
U '
SER S
Execute
Time Note
2 I, X
DC-8297-03
Z380 ™
M
ANUAL