History
The IBM SSEC, demonstrated in January 1948, had the ability to modify its instructions or otherwise treat them exactly like data. However, the capability was rarely used in practice. In the early days of computers, self-modifying code was often used to reduce use of limited memory, or improve performance, or both. It was also sometimes used to implement subroutine calls and returns when the instruction set only provided simple branching or skipping instructions to vary the control flow. This use is still relevant in certain ultra-RISC architectures, at least theoretically; see for example one instruction set computer. Donald Knuth's MIX architecture also used self-modifying code to implement subroutine calls.
Read more about this topic: Self-modifying Code
Famous quotes containing the word history:
“The history of reform is always identical; it is the comparison of the idea with the fact. Our modes of living are not agreeable to our imagination. We suspect they are unworthy. We arraign our daily employments.”
—Ralph Waldo Emerson (18031882)
“The history of literaturetake the net result of Tiraboshi, Warton, or Schlegel,is a sum of a very few ideas, and of very few original tales,all the rest being variation of these.”
—Ralph Waldo Emerson (18031882)
“The history of mens opposition to womens emancipation is more interesting perhaps than the story of that emancipation itself.”
—Virginia Woolf (18821941)