implemented several simple floating point routines

c64/basic/math/mov_FAC2_FAC1.s

@@ -0,0 +1,49 @@
+// #LAYOUT# STD *       #TAKE
+// #LAYOUT# *   BASIC_0 #TAKE
+// #LAYOUT# *   *       #IGNORE
+
+//
+// Math package - copy FAC2 to FAC1
+//
+// Output (found by experimentation):
+// - .A - FAC1 exponent
+// - .X - always 0
+//
+// Preserves:
+// - .Y
+//
+// See also:
+// - [CM64] Computes Mapping the Commodore 64 - page 115
+// - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
+// - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
+//
+
+mov_FAC2_FAC1:
+
+	// Copy the mantissa
+
+	lda FAC2_mantissa+3
+	sta FAC1_mantissa+3
+	lda FAC2_mantissa+2
+	sta FAC1_mantissa+2
+	lda FAC2_mantissa+1
+	sta FAC1_mantissa+1
+	lda FAC2_mantissa+0
+	sta FAC1_mantissa+0
+
+	// Copy the sign
+
+	lda FAC2_sign
+	sta FAC1_sign
+
+	// Copy the exponent
+
+	lda FAC2_exponent
+	sta FAC1_exponent
+
+	// Clear FACOV
+
+	ldx #$00
+	stx FACOV
+
+	rts