Modula-2 Basic Data Types
This section documents the memory formats used to represent the data values in the Modula-2 language. For each type, the number of bytes used and the interpretation of the data is given.
| Type | Storage size | Range |
| INTEGER | 16-bit compiler: 2 bytes 32-bit compiler: 4 bytes |
-32768 to 32767 -2,147,483,648 to 2,147,483,647 |
| CARDINAL | 16-bit compiler: 2 bytes 32-bit compiler: 4 bytes |
0 to 65535 0 to 4,294,967,295 |
| REAL | 4 bytes | Real numbers with an approximate range of 8.43E-37 to 3.37E+38 and an accuracy of about 6 decimal digits |
| LONGREAL | 8 bytes | Real numbers with an approximate range of 4.19E-307 to 1.67E+308 and an accuracy of about 15 decimal digits |
| COMPLEX | 8 bytes | Complex numbers where the real and imaginary Components are of type REAL |
| LONGCOMPLEX | 16 bytes | Complex numbers where the real and imaginary Components are of type LONGREAL |
| BOOLEAN | 1 byte | An enumeration type with the values FALSE and TRUE |
| CHAR | ANSI (8-bit): 1 byte UNICODE (16-bit): 2 bytes |
A character in the ANSI (8-bit) or UNICODE (16-bit) character set. Character type selectable via a compiler option. |
| BITSET | 2 bytes | A PACKEDSET type with an ordinal range of CARDINAL[0..15] |
| SHORTINT * | 1 byte | Integer values in the range of -128 to 127 |
| SHORTCARD * | 1 byte | Integer values in the range of 0 to 255 |
| INTEGER8 * | 1 byte | Integer values in the range of -128 to 127 |
| CARDINAL8 * | 1 byte | Integer values in the range of 0 to 255 |
| INTEGER16 * | 2 bytes | Integer values in the range of -32768 to 32767 |
| CARDINAL16 * | 2 bytes | Integer values in the range of 0 to 65535 |
| INTEGER32 * | 4 bytes | Integer values in the range of -2,147,483,648 to 2,147,483,647 |
| CARDINAL32 * | 4 bytes | Integer values in the range of 0 to 4,294,967,295 |
| INTEGER64 * | 8 bytes | 32-bit mode only. Integer values in the range of -2**63 to (2**63)-1 |
| CARDINAL64 * | 8 bytes | 32-bit mode only. Integer values in the range of 0 to (2**64)-1 Note: The compiler performs all compile time arithmetic with the INTEGER64 type, therefore constants larger than MAX(INTEGER64) are not supported. The MAX function is supported. |
| LONGINT * | 16-bit compiler: 4 bytes 32-bit compiler: 8 bytes |
Integer values in the range of -2,147,483,648 to 2,147,483,647 -2**63 to (2**63)-1 |
| LONGCARD * | 16-bit compiler: 4 bytes 32-bit compiler: 8 bytes |
Integer values in the range of 0 to 4,294,967,295 0 to (2**64)-1 Note: See CARDINAL64. |
| ACHAR * | 1 byte | A character in the ANSI (8-bit) character set |
| UCHAR * | 2 bytes | A character in the UNICODE (16-bit) character set |
| BYTEBOOL * BOOL8 * |
1 byte | An enumeration type with the values FALSE and TRUE |
| WORDBOOL * BOOL16 * | 2 bytes | An enumeration type with the values FALSE and TRUE |
| DWORDBOOL * BOOL32 * | 4 bytes | An enumeration type with the values FALSE and TRUE. Useful when interfacing with C code. |
| BITSET16 * | 2 bytes | A PACKEDSET type with an ordinal range of CARDINAL[0..15] |
| BITSET32 * | 4 bytes | A PACKEDSET type with an ordinal range of CARDINAL[0..31] |
* An extended type specific to Stony Brook Modula-2.