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Assembly Language
character and string operations
summary
This web page examines string and character instructions in assembly language. Specific examples of instructions from various processors are used to illustrate the general nature of assembly language.
For those with high speed connections, the very large single file summary is still on line.
string and character operations
- MVC MoVe Character; IBM 360/370; SS format; moves one to 256 characters (8 bits each) of data; main storage to main storage only; does not affect condition code
- CMPC3 Compare Characters 3 Operand; DEC VAX; compares two character strings designated by a length and two source addresses, indicating if they are the same or different; sets Z flag if two strings are equal and sets registers to indicate position where the two strings differed
- CMPC5 Compare Characters 5 Operand; DEC VAX; compares two character strings designated by two lengths and two source addresses, indicating if they are the same or different, virtually extending the shorter string with the designated fill character; sets Z flag if two strings are equal and sets registers to indicate position where the two strings differed
- LOCC Locate Character; DEC VAX; finds the character operand in the character string designated by the source string length and address; sets Z flag if the character is in the string and sets registers to indicate position, one register havingthe integer count and another register having the memory address
- MATCHC Match Characters; DEC VAX; searchs a string of specified legth and source address for a substring that matches the object string specified by the object length and object address; sets or clears Z flag (set if substring found, cleared if not)
- MOVC3 Move Character 3 Operand; DEC VAX; moves the character string of the designated length from the source address to the destination address, taking into account the possibility of overlapping memory blocks
- MOVC5 Move Character 5 Operand; DEC VAX; moves the character string of the designated length and source address to the destination length and address, taking into account the possibility of overlapping memory blocks, truncating if the source is larger than the destination and using the designated fill character if the destination is larger than the source
- MOVTC Move Translated Characters; DEC VAX; moves the character string of the designated length and source address to the destination length and address, using the designated translation table (256 entries), taking into account the possibility of overlapping memory blocks, truncating if the source is larger than the destination and using the designated fill character if the destination is larger than the source
- MOVTUC Move Translated Until Character; DEC VAX; moves the character string of the designated length and source address to the destination length and address, using the designated translation table (256 entries), stopping when encountering the designated escape character, taking into account the possibility of overlapping memory blocks, truncating if the source is larger than the destination and using the designated fill character if the destination is larger than the source
- SCANC Scan Characters; DEC VAX; scans the character string designated by the length and memory address using the designated table and mask, each character being used as an index into the table, the resulting table entry bit ANDed with the mask operand until the result of the AND is non-zero or the string is exhausted, giving the integer count and the memory address of the byte producing the non-zero AND result or zero count for exhausting the string without a non-zero result
- SPANC Span Characters; DEC VAX; scans the character string designated by the length and memory address using the designated table and mask, each character being used as an index into the table, the resulting table entry bit ANDed with the mask operand until the result of the AND is zero or the string is exhausted, giving the integer count and the memory address of the byte producing the zero AND result or zero count for exhausting the string without a zero result
- SKPC Skip Characters; DEC VAX; compares the character operand with the string designated by the length and memory address until an inequality is located or the string is exhausted, giving the integer count and memory address of the byte producing inequality or zero count for exhausting the string without inequality
See also character codes (ASCII, EBCDIC, etc.).
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Created: February 21, 2001 (from machcode.htm)
Last Updated: November 28, 2010
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