Added PseudoRandom

Author: intoinside

lib/random-global.asm

@@ -0,0 +1,5 @@
+#import "random.asm"
+#importonce
+.filenamespace c128lib
+
+.macro @c128lib_PseudoRandom() { PseudoRandom() }

lib/random.asm

@@ -0,0 +1,35 @@
+/*
+ * c128lib (c) 2023
+ * https://github.com/c128lib/framework
+ */
+
+// #import "chipset/lib/vic2.asm"
+
+#importonce
+.filenamespace c128lib
+
+.namespace Random {
+}
+
+/*
+  Generates a random number starting from a given seed.
+  It's not a real random number generator but generates
+  a pseudo random number. By passing the same seed, it will
+  generate always the same number. It is guaranteed to create a 
+  sequence touching every element just once.
+  Seed must be provided in accumulator and can be from 0 to $ff.
+  Output number will be available in the accumulator.
+
+  Params:
+  .A - Seed
+
+*/
+.macro PseudoRandom() {
+    beq doEor
+    asl
+    beq noEor
+    bcc noEor
+doEor:
+    eor #$1d
+noEor:
+}