M1750 Ada Technical Summary: For mission-critical applications | ||
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Declarations and types are supported as specified in the Ada standard except for tagged types (See RM Section 3.9).
When the compile time option -Wuninitialized is used, the compiler flags variables that may be uninitialized.
Enumeration types are supported as defined in the Ada 95 Reference Manual. Additional code and read-only data are generated to support the attributes 'Image, 'Pos and 'Val.
The size of enumeration objects is the minimum required to accommodate all the values, and including any representations given in a representation clause. The compiler selects a size of 16 or 32 bits as appropriate.
Enumeration types may be packed to reduce wasted space in arrays of enumeration objects.
M1750 Ada provides five predefined Integer types:
the type Short_Short_Integer
the type Short_Integer
the type Integer
the type Long_Integer
the type Long_Long_Integer
Table 3-1 gives the values of the attributes Size, First and Last for these types.
Table 3-1. Attributes of the Predefined Integer Types
Type | Size | First | Last |
---|---|---|---|
Short_Short_Integer | 16 | -215 | 215-1 |
Short_Integer | 16 | -215 | 215-1 |
Integer | 16 | -215 | 215-1 |
Long_Integer | 32 | -231 | 231-1 |
Long_Long_Integer | 64 | -263 | 263-1 |
User-Defined Types. For a user-defined integer type, the compiler automatically selects the smallest compatible predefined integer type as the base type. For example, given the following type definition:
the compiler uses Short_Short_Integer as the base type, and My_Integer'Size is 16 bits.
Modular Types. M1750 Ada supports modular types up to 64 bits in size. Like the integer types, these are represented in 16, 32 or 64 bits as appropriate. The value of Max_Nonbinary_Modulus is 32767. The following declarations are legal:
type Unsigned_8 is mod 256; type Unsigned_16 is mod 65536; type Unsigned_32 is mod 2**32; type Unsigned_64 is mod 2**64; type Index is mod 32767;
The standard Ada 95 operators for modular types are supported.
M1750 Ada provides four predefined floating-point types:
the type Short_Float
the type Float
the type Long_Float
the type Long_Long_Float
The types Short_Float and Float are represented by the 32-bit single precision 1750 format; the types Long_Float and Long_Long_Float are represented by the 48-bit 1750 format.
Table 3-2 gives the values of the attributes for the predefined floating-point types.
Table 3-2. Basic Attributes of Floating Point Types
Attribute | Short Float | Float | Long Float | Long Long Float |
---|---|---|---|---|
Size | 32 | 32 | 48 | 48 |
Digits | 6 | 6 | 9 | 9 |
Machine_Radix | 2 | 2 | 2 | 2 |
Machine_Mantissa | 23 | 23 | 39 | 39 |
Machine_Emax | 127 | 127 | 127 | 127 |
Machine_Emin | -128 | -128 | -128 | -128 |
Machine_Rounds | False | False | False | False |
Machine_Overflows | False | False | False | False |