(* Library module defined by the International Standard Information technology - programming languages BS ISO/IEC 10514-1:1996E Part 1: Modula-2, Base Language. Copyright ISO/IEC (International Organization for Standardization and International Electrotechnical Commission) 1996-2021. It may be freely copied for the purpose of implementation (see page 707 of the Information technology - Programming languages Part 1: Modula-2, Base Language. BS ISO/IEC 10514-1:1996). *) DEFINITION MODULE SYSTEM; (* Gives access to system programming facilities that are probably non portable. *) (* The constants and types define underlying properties of storage *) EXPORT QUALIFIED BITSPERLOC, LOCSPERWORD, LOC, BYTE, WORD, ADDRESS, CSIZE_T, CSSIZE_T, (* @SYSTEM_DATATYPES@ *) ADDADR, SUBADR, DIFADR, MAKEADR, ADR, ROTATE, SHIFT, CAST, TSIZE, (* Internal GM2 compiler functions *) ShiftVal, ShiftLeft, ShiftRight, RotateVal, RotateLeft, RotateRight, THROW, TBITSIZE ; CONST (* ; *) BITSPERLOC = __ATTRIBUTE__ __BUILTIN__ ((BITS_PER_UNIT)) ; (* ; *) LOCSPERWORD = __ATTRIBUTE__ __BUILTIN__ ((UNITS_PER_WORD)) ; (* ; *) LOCSPERBYTE = 8 DIV BITSPERLOC ; (* Note that the full list of system and sized datatypes include: LOC, WORD, BYTE, ADDRESS, (and the non language standard target types) INTEGER8, INTEGER16, INTEGER32, INTEGER64, CARDINAL8, CARDINAL16, CARDINAL32, CARDINAL64, WORD16, WORD32, WORD64, BITSET8, BITSET16, BITSET32, REAL32, REAL64, REAL128, COMPLEX32, COMPLEX64, COMPLEX128, CSIZE_T, CSSIZE_T. Also note that the non-standard data types will move into another module in the future. *) (* All the data types and procedures below are declared internally. =============================================================== TYPE @SYSTEM_TYPES@ TYPE LOC; (* A system basic type. Values are the uninterpreted contents of the smallest addressable unit of storage *) ADDRESS = POINTER TO LOC; WORD = ARRAY [0 .. LOCSPERWORD-1] OF LOC; (* BYTE and LOCSPERBYTE are provided if appropriate for machine *) TYPE BYTE = ARRAY [0 .. LOCSPERBYTE-1] OF LOC; PROCEDURE ADDADR (addr: ADDRESS; offset: CARDINAL): ADDRESS; (* Returns address given by (addr + offset), or may raise an exception if this address is not valid. *) PROCEDURE SUBADR (addr: ADDRESS; offset: CARDINAL): ADDRESS; (* Returns address given by (addr - offset), or may raise an exception if this address is not valid. *) PROCEDURE DIFADR (addr1, addr2: ADDRESS): INTEGER; (* Returns the difference between addresses (addr1 - addr2), or may raise an exception if the arguments are invalid or address space is non-contiguous. *) PROCEDURE MAKEADR (high: ; ...): ADDRESS; (* Returns an address constructed from a list of values whose types are implementation-defined, or may raise an exception if this address is not valid. In GNU Modula-2, MAKEADR can take any number of arguments which are mapped onto the type ADDRESS. The first parameter maps onto the high address bits and subsequent parameters map onto lower address bits. For example: a := MAKEADR(BYTE(0FEH), BYTE(0DCH), BYTE(0BAH), BYTE(098H), BYTE(076H), BYTE(054H), BYTE(032H), BYTE(010H)) ; then the value of, a, on a 64 bit machine is: 0FEDCBA9876543210H The parameters do not have to be the same type, but constants _must_ be typed. *) PROCEDURE ADR (VAR v: ): ADDRESS; (* Returns the address of variable v. *) PROCEDURE ROTATE (val: ; num: INTEGER): ; (* Returns a bit sequence obtained from val by rotating up/right or down/right by the absolute value of num. The direction is down/right if the sign of num is negative, otherwise the direction is up/left. *) PROCEDURE SHIFT (val: ; num: INTEGER): ; (* Returns a bit sequence obtained from val by shifting up/left or down/right by the absolute value of num, introducing zeros as necessary. The direction is down/right if the sign of num is negative, otherwise the direction is up/left. *) PROCEDURE CAST (; val: ): ; (* CAST is a type transfer function. Given the expression denoted by val, it returns a value of the type . An invalid value for the target value or a physical address alignment problem may raise an exception. *) PROCEDURE TSIZE (; ... ): CARDINAL; (* Returns the number of LOCS used to store a value of the specified . The extra parameters, if present, are used to distinguish variants in a variant record. *) PROCEDURE THROW (i: INTEGER) <* noreturn *> ; (* THROW is a GNU extension and was not part of the PIM or ISO standards. It throws an exception which will be caught by the EXCEPT block (assuming it exists). This is a compiler builtin function which interfaces to the GCC exception handling runtime system. GCC uses the term throw, hence the naming distinction between the GCC builtin and the Modula-2 runtime library procedure Raise. The later library procedure Raise will call SYSTEM.THROW after performing various housekeeping activities. *) PROCEDURE TBITSIZE () : CARDINAL ; (* Returns the minimum number of bits necessary to represent . This procedure function is only useful for determining the number of bits used for any type field within a packed RECORD. It is not particularly useful elsewhere since might be optimized for speed, for example a BOOLEAN could occupy a WORD. *) *) (* The following procedures are invoked by GNU Modula-2 to shift non word set types. They are not part of ISO Modula-2 but are used to implement the SHIFT procedure defined above. *) (* ShiftVal - is a runtime procedure whose job is to implement the SHIFT procedure of ISO SYSTEM. GNU Modula-2 will inline a SHIFT of a single WORD sized set and will only call this routine for larger sets. *) PROCEDURE ShiftVal (VAR s, d: ARRAY OF BITSET; SetSizeInBits: CARDINAL; ShiftCount: INTEGER) ; (* ShiftLeft - performs the shift left for a multi word set. This procedure might be called by the back end of GNU Modula-2 depending whether amount is known at compile time. *) PROCEDURE ShiftLeft (VAR s, d: ARRAY OF BITSET; SetSizeInBits: CARDINAL; ShiftCount: CARDINAL) ; (* ShiftRight - performs the shift left for a multi word set. This procedure might be called by the back end of GNU Modula-2 depending whether amount is known at compile time. *) PROCEDURE ShiftRight (VAR s, d: ARRAY OF BITSET; SetSizeInBits: CARDINAL; ShiftCount: CARDINAL) ; (* RotateVal - is a runtime procedure whose job is to implement the ROTATE procedure of ISO SYSTEM. GNU Modula-2 will inline a ROTATE of a single WORD (or less) sized set and will only call this routine for larger sets. *) PROCEDURE RotateVal (VAR s, d: ARRAY OF BITSET; SetSizeInBits: CARDINAL; RotateCount: INTEGER) ; (* RotateLeft - performs the rotate left for a multi word set. This procedure might be called by the back end of GNU Modula-2 depending whether amount is known at compile time. *) PROCEDURE RotateLeft (VAR s, d: ARRAY OF BITSET; SetSizeInBits: CARDINAL; RotateCount: CARDINAL) ; (* RotateRight - performs the rotate right for a multi word set. This procedure might be called by the back end of GNU Modula-2 depending whether amount is known at compile time. *) PROCEDURE RotateRight (VAR s, d: ARRAY OF BITSET; SetSizeInBits: CARDINAL; RotateCount: CARDINAL) ; END SYSTEM.