11 Any item enclosed by curly brackets, ( , is optional Sometimes {} are actual symbols in syntax, for example when theysurroundaregisterlistARM042019-3-14
{ } ARM04 2019-3-14 11 Any item enclosed by curly brackets, { }, is optional Sometimes { } are actual symbols in syntax, for example when they surround a register list
[]12Anyitems enclosedby squarebrackets,[],constitutea listofalternative characters Sometimes[] arepart of syntax,suchas addressingmodes orvectorelementsARMO42019-3-14
[ ] ARM04 2019-3-14 12 Any items enclosed by square brackets, [ ], constitute a list of alternative characters Sometimes [ ] are part of syntax, such as addressing modes or vector elements
(a/b)13 Alternative words are separated by a vertical bar, I, and can besurroundedbyparentheses For example, U(ADD|SUB)W is UADDW or USUBWARMO42019-3-14
(a|b) ARM04 2019-3-14 13 Alternative words are separated by a vertical bar, |, and can be surrounded by parentheses For example, U(ADD|SUB)W is UADDW or USUBW
十14 This indicates an optional + or-sign If neither is used then + is assumedARM042019-3-14
± ARM04 2019-3-14 14 This indicates an optional + or - sign If neither is used then + is assumed
#15isusedbeforeanimmediateoperandARM042019-3-14
# ARM04 2019-3-14 15 is used before an immediate operand