1 files changed, 78 insertions, 0 deletions
diff --git a/system/base/1.7.5/src/bits b/system/base/1.7.5/src/bits
new file mode 100644
index 0000000..e9e84e7
--- /dev/null
+++ b/system/base/1.7.5/src/bits
@@ -0,0 +1,78 @@
+
+PACKET bits DEFINES
+
+    AND ,
+    OR ,
+    XOR ,
+    bit ,
+    lowest reset ,
+    lowest set ,
+    reset bit ,
+    rotate ,
+    set bit :
+
+LET bits per int = 16 ;
+
+ROW bits per int INT VAR bit mask := ROW bits per int INT:
+    (1,2,4,8,16,32,64,128,256,512,1024,2048,4096,8192,16384,-32767-1) ;
+
+PROC rotate (INT VAR bits, INT CONST number of bits) :
+  EXTERNAL 83
+ENDPROC rotate ;
+
+INT OP AND (INT CONST left, right) :
+  EXTERNAL 124
+ENDOP AND ;
+
+INT OP OR (INT CONST left, right) :
+  EXTERNAL 125
+ENDOP OR ;
+
+INT OP XOR (INT CONST left, right) :
+  EXTERNAL 121
+ENDOP XOR ;
+
+BOOL PROC bit (INT CONST bits, bit no) :
+
+  (bits AND bit mask (bit no+1)) <> 0
+
+ENDPROC bit ;
+
+PROC set bit (INT VAR bits, INT CONST bit no) :
+
+  bits := bits OR bit mask (bit no+1)
+
+ENDPROC set bit ;
+
+PROC reset bit (INT VAR bits,INT CONST bit no) :
+
+  bits := bits XOR (bits AND bit mask (bit no+1))
+
+ENDPROC reset bit ;
+
+INT PROC lowest set (INT CONST bits) :
+
+  INT VAR mask index ;
+  FOR mask index FROM 1 UPTO 16 REP
+    IF (bits AND bit mask (mask index)) <> 0
+      THEN LEAVE lowest set WITH mask index - 1
+    FI
+  PER ;
+  -1
+
+ENDPROC lowest set ;
+
+INT PROC lowest reset (INT CONST bits) :
+
+  INT VAR mask index ;
+  FOR mask index FROM 1 UPTO bits per int REP
+    IF (bits AND bit mask (mask index)) = 0
+      THEN LEAVE lowest reset WITH mask index - 1
+    FI
+  PER ;
+  -1
+
+ENDPROC lowest reset ;
+
+ENDPACKET bits ;
+