Atmel CAVR-4 Manual De Usuario
CAVR-4
Part 2. Compiler reference
Implementation-defined behavior
259
Demoting floating-point values (6.2.1.4)
When a floating-point value is converted to a floating-point value of narrower type that
cannot exactly represent the value, the value is rounded (up or down) to the nearest
suitable value.
cannot exactly represent the value, the value is rounded (up or down) to the nearest
suitable value.
ARRAYS AND POINTERS
size_t (6.3.3.4, 7.1.1)
See size_t, page 142, for information about
size_t
.
Conversion from/to pointers (6.3.4)
See Casting, page 142, for information about casting of data pointers and function
pointers.
pointers.
ptrdiff_t (6.3.6, 7.1.1)
See ptrdiff_t, page 143, for information about the
ptrdiff_t
.
REGISTERS
Honoring the register keyword (6.5.1)
User requests for register variables are not honored.
STRUCTURES, UNIONS, ENUMERATIONS, AND BITFIELDS
Improper access to a union (6.3.2.3)
If a union gets its value stored through a member and is then accessed using a member
of a different type, the result is solely dependent on the internal storage of the first
member.
of a different type, the result is solely dependent on the internal storage of the first
member.
Padding and alignment of structure members (6.5.2.1)
See the section Basic data types, page 138, for information about the alignment
requirement for data objects.
requirement for data objects.
Sign of 'plain' bitfields (6.5.2.1)
A 'plain'
int
bitfield is treated as a signed
int
bitfield. All integer types are allowed as
bitfields.