Built in Functions

These functions are supported in GPU code:

Arithmetic operations

• abs
  Translated to C (f|ll)abs(f) functions, depending on the argument type.

• + – * / 1+ 1-
  These operations are directly translated to C arithmetic operators, and thus follow C type promotion and rounding rules: e.g, integer division truncates.

As a special exception (/ x) always returns a floating-point value because it would be useless and dangerous otherwise.

Boolean operations and comparisons

• t nil
  These constants are interpreted as having boolean type, but nil may be used as an init expression for a declared variable of any type to specify the lack of initialization.

• and or
  These support only boolean arguments, and return booleans.

• zerop < <= = /= >= >
• max min
  Should work as documented.

• nonzerop
  A counterpart to zerop, defined by this package.

• eq eql
  Basically equivalent to =, implemented for better macro support.

Bitwise logic operations

• logand logior logxor logeqv lognot
• logandc1 logandc2 lognand lognor logorc1 logorc2

Transcendental functions

• sin asin sinh asinh
• cos acos cosh acosh
• tan atan tanh atanh
• exp sqrt log expt

These function are mapped to C standard library calls and have equivalent precision. In cases when the result would normally be a complex value, NaN is returned.

Rounding functions

Unlike the standard lisp library versions, these functions return only one value:

• ffloor fceiling ftruncate fround
  Implemented via equivalent library calls; always return a floating point-value.

• floor ceiling truncate round
  Always return an integer. In complex cases implemented via the floating-point equivalents.

Array access functions

• array-total-size array-dimension aref
  Similar to the lisp versions.

• (raw-aref array index)
  Due to the frequent use of pitched allocation to achieve perfect data alignment in gpu arrays, row-major-aref is difficult to implement transparently. This is its functional equivalent that acknowledges the presense of alignment holes in its index range.

• (array-raw-extent array)
  Returns the size of the index range for raw-aref. For pitched arrays it is greater than array-total-size.

• (array-raw-stride array dim-idx)
  Returns the stepping for the corresponding dimension with corrections for pitch.

(aref a i j k) = (raw-aref a (+ (* i (array-raw-stride a 0)) (* j (array-raw-stride a 1)) k))

The value of the array parameter must be statically resolvable to the original global variable, kernel parameter or fully declared local array variable.