A floating-point literal is a string of decimal digits followed by a required decimal point, an optional fractional portion, and an optional exponent portion. The syntax for a floating-point number is:
| [ +|- ] nnn . [ nnn] [ E|e [ +|- ] nnn ] |
Replace nnn with a string of decimal digits. You can precede nnn with a + or a -. You must specify a decimal point. For example, 3.e5 is valid, but 3e5 is not valid. The exponent indicates a power of 10. These are examples of valid floating-point literals:
3.0
3.14
3.
-0.314e13
+314.59e-2
The assembler syntax does not support all C89-style float literals nor C99-style hexadecimal constants, but the $$strtod built-in mathematical function supports both. If you want to specify a floating-point literal using one of those formats, use $$strtod. For example:
$$strtod(".3")
$$strtod("0x1.234p-5")
You cannot directly use NaN, Inf, or -Inf as floating-point literals. Instead, use $$strtod to express these values. The "NaN" and "Inf" strings are handled case-insensitively. See Section 4.10.1 for built-in functions.
$$strtod("NaN")
$$strtod("Inf")