ARM Compiler toolchain Using the Assembler: Unary operators

Unary operators

Unary operators have the highest precedence and are evaluated first. A unary operator precedes its operand. Adjacent operators are evaluated from right to left.

Table 27 lists the unary operators that return strings.

Table 27. Unary operators that return strings

Operator	Usage	Description
`:CHR:`	`:CHR:A`	Returns the character with ASCII code A.
`:LOWERCASE:`	`:LOWERCASE:string`	Returns the given string, with all uppercase characters converted to lowercase.
`:REVERSE_CC:`	`:REVERSE_CC:cond_code`	Returns the inverse of the condition code in `cond_code`, or an error if `cond_code` does not contain a valid condition code.
`:STR:`	`:STR:A`	Returns an 8-digit hexadecimal string corresponding to a numeric expression, or the string `"T"` or `"F"` if used on a logical expression.
`:UPPERCASE:`	`:UPPERCASE:string`	Returns the given string, with all lowercase characters converted to uppercase.

Table 28 lists the unary operators that return numeric values.

Table 28. Unary operators that return numeric or logical values

Operator	Usage	Description
`?`	`?A`	Number of bytes of executable code generated by line defining symbol A.
`+` and `-`	`+A` `-A`	Unary plus. Unary minus. + and - can act on numeric and PC-relative expressions.
`:BASE:`	`:BASE:A`	If A is a PC-relative or register-relative expression, `:BASE:` returns the number of its register component. `:BASE:` is most useful in macros.
`:CC_ENCODING:`	`:CC_ENCODING:cond_code`	Returns the numeric value of the condition code in `cond_code`, or an error if `cond_code` does not contain a valid condition code.
`:DEF:`	`:DEF:A`	{`TRUE`} if A is defined, otherwise {`FALSE`}.
`:INDEX:`	`:INDEX:A`	If A is a register-relative expression, `:INDEX:` returns the offset from that base register. `:INDEX:` is most useful in macros.
`:LEN:`	`:LEN:A`	Length of string A.
`:LNOT:`	`:LNOT:A`	Logical complement of A.
`:NOT:`	`:NOT:A`	Bitwise complement of A (`~` is an alias, for example `~A`).
`:RCONST:`	`:RCONST:Rn`	Number of register, 0-15 corresponding to R0-R15.

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Unary operators

See also