}
} ;
-HELP: bits
+HELP: bits
{ $values { "m" integer } { "n" integer } { "m'" integer } }
{ $description "Keep only n bits from the integer m." }
-{ $example "USING: math.bitwise prettyprint ;" "HEX: 123abcdef 16 bits .h" "cdef" } ;
+{ $example "USING: math.bitwise prettyprint ;" "0x123abcdef 16 bits .h" "cdef" } ;
HELP: bitroll
{ $values { "x" integer } { "s" "a shift integer" } { "w" "a wrap integer" } { "y" integer }
{ $description "Roll n by s bits to the left, wrapping around after w bits." }
{ $examples
{ $example "USING: math.bitwise prettyprint ;" "1 -1 32 bitroll .b" "10000000000000000000000000000000" }
- { $example "USING: math.bitwise prettyprint ;" "HEX: ffff0000 8 32 bitroll .h" "ff0000ff" }
+ { $example "USING: math.bitwise prettyprint ;" "0xffff0000 8 32 bitroll .h" "ff0000ff" }
} ;
HELP: bit-clear?
{ "?" "a boolean" }
}
{ $description "Returns " { $link t } " if the nth bit is set to zero." }
-{ $examples
+{ $examples
{ $example "USING: math.bitwise prettyprint ;"
- "HEX: ff 8 bit-clear? ."
+ "0xff 8 bit-clear? ."
"t"
}
- { $example "" "USING: math.bitwise prettyprint ;"
- "HEX: ff 7 bit-clear? ."
+ { $example "USING: math.bitwise prettyprint ;"
+ "0xff 7 bit-clear? ."
"f"
}
} ;
{ "n" integer }
}
{ $description "Returns the number of set bits as an object. This word only works on non-negative integers or objects that can be represented as a byte-array." }
-{ $examples
+{ $examples
{ $example "USING: math.bitwise prettyprint ;"
- "HEX: f0 bit-count ."
+ "0xf0 bit-count ."
"4"
}
{ $example "USING: math.bitwise prettyprint ;"
HELP: bitroll-32
{ $values
- { "n" integer } { "s" integer }
- { "n'" integer }
-}
-{ $description "Rolls the number " { $snippet "n" } " by " { $snippet "s" } " bits to the left, wrapping around after 32 bits." }
-{ $examples
+ { "m" integer } { "s" integer }
+ { "n" integer }
+}
+{ $description "Rolls the number " { $snippet "m" } " by " { $snippet "s" } " bits to the left, wrapping around after 32 bits." }
+{ $examples
{ $example "USING: math.bitwise prettyprint ;"
- "HEX: 1 10 bitroll-32 .h"
+ "0x1 10 bitroll-32 .h"
"400"
}
{ $example "USING: math.bitwise prettyprint ;"
- "HEX: 1 -10 bitroll-32 .h"
+ "0x1 -10 bitroll-32 .h"
"400000"
}
} ;
HELP: bitroll-64
{ $values
- { "n" integer } { "s" "a shift integer" }
- { "n'" integer }
+ { "m" integer } { "s" "a shift integer" }
+ { "n" integer }
}
-{ $description "Rolls the number " { $snippet "n" } " by " { $snippet "s" } " bits to the left, wrapping around after 64 bits." }
-{ $examples
+{ $description "Rolls the number " { $snippet "m" } " by " { $snippet "s" } " bits to the left, wrapping around after 64 bits." }
+{ $examples
{ $example "USING: math.bitwise prettyprint ;"
- "HEX: 1 10 bitroll-64 .h"
+ "0x1 10 bitroll-64 .h"
"400"
}
{ $example "USING: math.bitwise prettyprint ;"
- "HEX: 1 -10 bitroll-64 .h"
+ "0x1 -10 bitroll-64 .h"
"40000000000000"
}
} ;
{ $description "Sets the nth bit of " { $snippet "x" } " to zero." }
{ $examples
{ $example "USING: math.bitwise kernel prettyprint ;"
- "HEX: ff 7 clear-bit .h"
+ "0xff 7 clear-bit .h"
"7f"
}
} ;
-HELP: flags
-{ $values { "values" sequence } }
-{ $description "Constructs a constant flag value from a sequence of integers or words that output integers. The resulting constant is computed at compile-time, which makes this word as efficient as using a literal integer." }
-{ $examples
- { $example "USING: math.bitwise kernel prettyprint ;"
- "IN: scratchpad"
- "CONSTANT: x HEX: 1"
- "{ HEX: 20 x BIN: 100 } flags .h"
- "25"
- }
-} ;
-
HELP: symbols>flags
{ $values { "symbols" sequence } { "assoc" assoc } { "flag-bits" integer } }
{ $description "Constructs an integer value by mapping the values in the " { $snippet "symbols" } " sequence to integer values using " { $snippet "assoc" } " and " { $link bitor } "ing the values together." }
}
} ;
+HELP: >even
+{ $values
+ { "m" integer }
+ { "n" integer }
+}
+{ $examples
+ { $example "USING: math.bitwise prettyprint ;"
+ "7 >even ."
+ "6"
+ }
+}
+{ $description "Sets the lowest bit in the integer to 0, which either does nothing or outputs 1 less than the input integer." } ;
+
+HELP: >odd
+{ $values
+ { "m" integer }
+ { "n" integer }
+}
+{ $examples
+ { $example "USING: math.bitwise prettyprint ;"
+ "4 >odd ."
+ "5"
+ }
+}
+{ $description "Sets the lowest bit in the integer to 1, which either does nothing or outputs 1 more than the input integer." } ;
+
+HELP: >signed
+{ $values
+ { "x" integer } { "n" integer }
+ { "y" integer }
+}
+{ $examples
+ { $example "USING: math.bitwise prettyprint ;"
+ "0xff 8 >signed ."
+ "-1"
+ }
+}
+{ $description "Interprets a number " { $snippet "x" } " as an " { $snippet "n" } "-bit number and converts it to a negative number " { $snippet "n" } "-bit number if the topmost bit is set." } ;
+
HELP: mask
{ $values
{ "x" integer } { "n" integer }
{ $description "After the operation, only the bits that were set in both the mask and the original number are set." }
{ $examples
{ $example "USING: math.bitwise kernel prettyprint ;"
- "BIN: 11111111 BIN: 101 mask .b"
+ "0b11111111 0b101 mask .b"
"101"
}
} ;
{ $description "Turns off all bits besides the nth bit." }
{ $examples
{ $example "USING: math.bitwise kernel prettyprint ;"
- "HEX: ff 2 mask-bit .b"
+ "0xff 2 mask-bit .b"
"100"
}
} ;
{ $description "Returns true if all of the bits in the mask " { $snippet "n" } " are set in the integer input " { $snippet "x" } "." }
{ $examples
{ $example "USING: math.bitwise kernel prettyprint ;"
- "HEX: ff HEX: f mask? ."
+ "0xff 0xf mask? ."
"t"
}
{ $example "USING: math.bitwise kernel prettyprint ;"
- "HEX: f0 HEX: 1 mask? ."
+ "0xf0 0x1 mask? ."
"f"
}
} ;
HELP: on-bits
{ $values
- { "n" integer }
{ "m" integer }
+ { "n" integer }
}
-{ $description "Returns an integer with " { $snippet "n" } " bits set." }
+{ $description "Returns an integer with " { $snippet "m" } " bits set." }
{ $examples
{ $example "USING: math.bitwise kernel prettyprint ;"
"6 on-bits .h"
"1000"
}
{ $example "USING: math.bitwise kernel prettyprint ;"
- "BIN: 1000 3 toggle-bit .b"
+ "0b1000 3 toggle-bit .b"
"0"
}
} ;
HELP: shift-mod
{ $values
- { "n" integer } { "s" integer } { "w" integer }
+ { "m" integer } { "s" integer } { "w" integer }
{ "n" integer }
}
{ $description "Calls " { $link shift } " on " { $snippet "n" } " and " { $snippet "s" } ", wrapping the result to " { $snippet "w" } " bits." } ;
{ $description "Clears the bits in " { $snippet "x" } " if they are set in the mask " { $snippet "n" } "." }
{ $examples
{ $example "USING: math.bitwise kernel prettyprint ;"
- "HEX: ff HEX: 0f unmask .h"
+ "0xff 0x0f unmask .h"
"f0"
}
} ;
{ $description "Tests whether unmasking the bits in " { $snippet "x" } " would return an integer greater than zero." }
{ $examples
{ $example "USING: math.bitwise kernel prettyprint ;"
- "HEX: ff HEX: 0f unmask? ."
+ "0xff 0x0f unmask? ."
"t"
}
} ;
HELP: w*
{ $values
- { "int" integer } { "int" integer }
- { "int" integer }
+ { "x" integer } { "y" integer }
+ { "z" integer }
}
-{ $description "Multiplies two integers and wraps the result to 32 bits." }
+{ $description "Multiplies two integers and wraps the result to a 32-bit unsigned integer." }
{ $examples
{ $example "USING: math.bitwise kernel prettyprint ;"
- "HEX: ffffffff HEX: 2 w* ."
+ "0xffffffff 0x2 w* ."
"4294967294"
}
} ;
HELP: w+
{ $values
- { "int" integer } { "int" integer }
- { "int" integer }
+ { "x" integer } { "y" integer }
+ { "z" integer }
}
-{ $description "Adds two integers and wraps the result to 32 bits." }
+{ $description "Adds two integers and wraps the result to a 32-bit unsigned integer." }
{ $examples
{ $example "USING: math.bitwise kernel prettyprint ;"
- "HEX: ffffffff HEX: 2 w+ ."
+ "0xffffffff 0x2 w+ ."
"1"
}
} ;
HELP: w-
{ $values
- { "int" integer } { "int" integer }
- { "int" integer }
+ { "x" integer } { "y" integer }
+ { "z" integer }
}
-{ $description "Subtracts two integers and wraps the result to 32 bits." }
+{ $description "Subtracts two integers and wraps the result to a 32-bit unsigned integer." }
{ $examples
{ $example "USING: math.bitwise kernel prettyprint ;"
- "HEX: 0 HEX: ff w- ."
+ "0x0 0xff w- ."
"4294967041"
}
} ;
+HELP: W*
+{ $values
+ { "x" integer } { "y" integer }
+ { "z" integer }
+}
+{ $description "Multiplies two integers and wraps the result to a 64-bit unsigned integer." }
+{ $examples
+ { $example "USING: math.bitwise kernel prettyprint ;"
+ "0xffffffffffffffff 0x2 W* ."
+ "18446744073709551614"
+ }
+} ;
+
+HELP: W+
+{ $values
+ { "x" integer } { "y" integer }
+ { "z" integer }
+}
+{ $description "Adds two integers and wraps the result to 64-bit unsigned integer." }
+{ $examples
+ { $example "USING: math.bitwise kernel prettyprint ;"
+ "0xffffffffffffffff 0x2 W+ ."
+ "1"
+ }
+} ;
+
+HELP: W-
+{ $values
+ { "x" integer } { "y" integer }
+ { "z" integer }
+}
+{ $description "Subtracts two integers and wraps the result to a 64-bit unsigned integer." }
+{ $examples
+ { $example "USING: math.bitwise kernel prettyprint ;"
+ "0x0 0xff W- ."
+ "18446744073709551361"
+ }
+} ;
+
HELP: wrap
{ $values
{ "m" integer } { "n" integer }
}
{ $description "Wraps an integer " { $snippet "m" } " by modding it by " { $snippet "n" } ". This word is uses bitwise arithmetic and does not actually call the modulus word, and as such can only mod by powers of two." }
{ $examples "Equivalent to modding by 8:"
- { $example
+ { $example
"USING: math.bitwise prettyprint ;"
- "HEX: ffff 8 wrap .h"
+ "0xffff 8 wrap .h"
"7"
}
} ;
bit?
bit-clear?
}
+"Toggling a bit:"
+{ $subsections
+ toggle-bit
+}
"Operations with bitmasks:"
{ $subsections
mask
w-
w*
}
+"64-bit arithmetic:"
+{ $subsections
+ W+
+ W-
+ W*
+}
+"Converting a number to the nearest even/odd:"
+{ $subsections
+ >even
+ >odd
+}
"Bitfields:"
{ $subsections
- flags
"math-bitfields"
} ;
projects / factor.git / blobdiff