wilson@carcoar.Stanford.EDU (Paul Wilson) (03/12/90)
I'm looking for information on how good a Lisp compiler can be at keeping floating point values in registers, so that they don't have to be "boxed" into a heap format that keeps the gc happy. Perhaps some of the MacLisp or S-1 Lisp people have some idea about this. Roughly, the question is this: in floating-point intensive code, how frequent are loads and stores of heap floats relative to adds, multiplies, etc.? I figure I can squash a 32-bit IEEE float into a tagged word in about 7 cycles, and un-squash one into a standard float in about 5 cycles. I want to know how often I'll have to do this, compared to the actual floating-point work at hand. Thanks prematurely, Paul Paul R. Wilson Software Systems Laboratory lab ph.: (312) 996-9216 U. of Illin. at C. EECS Dept. (M/C 154) wilson@bert.eecs.uic.edu Box 4348 Chicago,IL 60680 Paul R. Wilson Software Systems Laboratory lab ph.: (312) 996-9216 U. of Illin. at C. EECS Dept. (M/C 154) wilson@bert.eecs.uic.edu Box 4348 Chicago,IL 60680