Update mov_FAC1_FAC2 to match the original implementation

src/basic/math_mov/bc0c.mov_r_FAC1_FAC2.s

@@ -3,13 +3,19 @@
 ;; #LAYOUT# *   BASIC_0 #TAKE
 ;; #LAYOUT# *   *       #IGNORE
 
+; This file is under the MIT license, it contains code released by Microsoft Corporation.
+; See LICENSE for more information.
+
 ;
 ; Math package - round and move FAC1 to FAC2
 ;
+; This is identical to the original Microsoft implementation where it was named MOVAF.
+;
 ; Output:
 ; - .A - FAC1 exponent
 ;
 ; See also:
+; - https://github.com/microsoft/BASIC-M6502/blob/7460af2c03ae19c0e60ff327489229d2005b9357/m6502.asm#L5540C1-L5548C12
 ; - [CM64] Computes Mapping the Commodore 64 - page 115
 ; - https://www.c64-wiki.com/wiki/BASIC-ROM
 ; - https://www.c64-wiki.com/wiki/Floating_point_arithmetic

src/basic/math_mov/bc0f.mov_FAC1_FAC2.jmp.s

@@ -1,8 +0,0 @@
-;; #LAYOUT# STD *       #TAKE
-;; #LAYOUT# X16 BASIC_0 #TAKE-OFFSET 2000
-;; #LAYOUT# *   BASIC_0 #TAKE
-;; #LAYOUT# *   *       #IGNORE
-
-; Just a compatibility jump - our routine is longer than original one
-
-	jmp mov_FAC1_FAC2

src/basic/math_mov/bc0f.mov_FAC1_FAC2.s

@@ -0,0 +1,41 @@
+;; #LAYOUT# STD *       #TAKE
+;; #LAYOUT# X16 BASIC_0 #TAKE-OFFSET 2000
+;; #LAYOUT# *   BASIC_0 #TAKE
+;; #LAYOUT# *   *       #IGNORE
+
+; This file is under the MIT license, it contains code released by Microsoft Corporation.
+; See LICENSE for more information.
+
+;
+; Math package - move FAC1 to FAC2
+;
+; This is verified to be identical to the original Microsoft implementation where it was named MOVEF.
+;
+; Output:
+; - .A - FAC1 exponent
+; - .X - always 0
+
+; Preserves:
+; - .Y
+;
+; Note:
+; - Always clears FACOV, not sure why
+;
+; See also:
+; - https://github.com/microsoft/BASIC-M6502/blob/7460af2c03ae19c0e60ff327489229d2005b9357/m6502.asm#L5540C1-L5548C12
+; - [CM64] Computes Mapping the Commodore 64 - page 115
+; - https://www.c64-wiki.com/wiki/BASIC-ROM
+; - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
+;
+
+mov_FAC1_FAC2:
+
+    ldx #6
+
+@1
+    lda FAC1_exponent - 1,X
+    sta FAC2_exponent - 1,X
+    dex
+    bne @1
+    stx FACOV           ; Always zero
+    rts

src/basic/math_mov/mov_FAC1_FAC2.s

@@ -1,51 +0,0 @@
-;; #LAYOUT# STD *       #TAKE
-;; #LAYOUT# *   BASIC_0 #TAKE
-;; #LAYOUT# *   *       #IGNORE
-
-;
-; Math package - move FAC1 to FAC2
-;
-; Output (all found by experimentation):
-; - .A - FAC1 exponent
-; - .X - always 0
-;
-; Preserves (found by experimentation):
-; - .Y
-;
-; Note:
-; - observed that original ROM always clears FACOV, not sure why
-;
-; See also:
-; - [CM64] Computes Mapping the Commodore 64 - page 115
-; - https://www.c64-wiki.com/wiki/BASIC-ROM
-; - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
-;
-
-mov_FAC1_FAC2:
-
-	; Copy the exponent
-	lda FAC1_exponent
-	sta FAC2_exponent
-	beq @1                             ; for 0 no need to copy mantissa and sign
-
-	; Copy the mantissa
-	lda FAC1_mantissa+0
-	sta FAC2_mantissa+0
-	lda FAC1_mantissa+1
-	sta FAC2_mantissa+1
-	lda FAC1_mantissa+2
-	sta FAC2_mantissa+2
-	lda FAC1_mantissa+3
-	sta FAC2_mantissa+3
-
-	; Copy the sign
-	lda FAC1_sign
-	sta FAC2_sign
-
-	lda FAC1_exponent
-@1:
-	; Duplicate the original ROM behaviour
-	ldx #$00
-	stx FACOV
-
-	rts