Aligning load/store data using rotate, mask, zero/sign-extend and or operation

A method for accessing a datum stored in a memory, the datum including a plurality of first bytes and a plurality of second bytes, wherein a word boundary separates the first bytes from the second bytes, the first bytes including one or more first desired bytes and one or more first undesired bytes, the second bytes including one or more second desired bytes and one or more second undesired bytes, the method comprising:

• reading the first bytes from the memory, the first bytes being a first portion of the datum and residing on a first side of the word boundary;
• performing a first rotation operation on the first bytes to produce first rotated bytes so that the first rotation operation isolates the first desired bytes from the first undesired bytes, thereby removing the first undesired bytes;
• performing a masking operation on portions of the first rotated bytes to produce first aligned bytes;
• performing a first sign extension operation on at least a portion of the first aligned bytes to extend a sign bit of the datum represented by the first aligned bytes to produce extended aligned bytes, thereby replacing the first undesired bytes with first additional known bytes;
• storing the extended aligned bytes to a first data register;
• reading the second bytes from the memory, the second bytes being a second portion of the datum and residing on a second side of the word boundary, the second side being different than the first side;
• performing a second rotation operation on the second bytes to produce second rotated bytes so that the second rotation operation isolates the second desired bytes from the second undesired bytes, thereby removing the second undesired bytes;
• performing a second sign extension operation on at least a portion of the second rotated bytes to produce second aligned bytes, thereby replacing the second undesired bytes with second additional known bytes;
• storing the second aligned bytes to a second data register;
• and
• performing an OR operation on the first aligned bytes and the second aligned bytes to produce a loaded datum.

A data processor for accessing a stored datum stored in a memory, the stored datum comprising a plurality of first bytes and a plurality of second bytes, wherein a word boundary separates the first bytes from the second bytes, the first bytes including one or more first desired bytes and one or more first undesired bytes, the second bytes including one or more second desired bytes and one or more second undesired bytes, the data processor comprising:

• a data input module configured to receive at least a portion of the stored datum from the memory;
• a rotator module coupled to the data input module and having a rotator output module, the rotator module configured to rotate the first bytes producing a first rotated datum and to rotate the second bytes producing a second rotated datum, the first rotated datum having the first desired bytes and not having the first undesired bytes, the second rotated datum having the second desired bytes and not having the second undesired bytes;
• a zero-filling module coupled to the rotator output module and configured to replace one or more bit positions of stored datum on the rotator output module with binary zeroes, the zero-filling module further configured to perform a sign extension operation to fill portions of the first rotated datum with binary zeroes thereby producing a first aligned datum and to perform a sign extension operation to fill portions of the second rotated datum with binary zeroes thereby producing a second aligned datum;
• and
• a logical operation module configured to perform an OR operation on the content of the first aligned datum and the second aligned datum, the OR operation result being a loaded datum.

A data processor system comprising:

• a memory, wherein a first datum and a second datum is stored in the memory, the first datum including a plurality of first bytes, the first bytes including one or more first desired bytes and one or more first undesired bytes, the second datum including a plurality of second bytes, the second bytes including one or more second desired bytes and one or more second undesired bytes;
• a data input module configured to receive at least a portion of the first datum from the memory and to receive at least a portion of the second datum from the memory;
• a rotator module coupled to the data input module and having a rotator output module, the rotator module configured to rotate the first bytes producing a first rotated datum and to rotate the second bytes producing a second rotated datum, the first rotated datum having the first desired bytes and not having the first undesired bytes, the second rotated datum having the second desired bytes and not having the second undesired bytes;
• a zero-filling module coupled to the rotator output module and configured to replace one or more bit positions of the first datum on the rotator output module with binary zeroes, the zero-filling module configured to perform a sign extension operation to fill portions of the first rotated datum with binary zeroes thereby producing a first aligned datum, the zero-filling module configured to perform a sign extension operation to fill portions of the second rotated datum with binary zeroes thereby producing a second aligned datum;
• and
• a logical operation module configured to perform an OR operation on the first aligned datum and the second aligned datum, wherein a result of the OR operation is a loaded first datum.