Update poly1_FAC1

src/aliases/,aliases_ram_lowmem.s

@@ -69,6 +69,7 @@
 	!addr FAC1_sign       = $66
 
 	!addr SGNFLG    = $67 ;          Also used as number of terms of series evaluation
+	!addr DEGREE    = SGNFLG
 	!addr BITS      = $68 ;          FAC1 overflow
 
 	!addr __FAC2    = $69 ; $69-$6E  floating point accumulator 2 [!] also used for memory move pointers
@@ -78,7 +79,8 @@
 
 	!addr ARISGN    = $6F ;          -- NOT IMPLEMENTED --
 	!addr FACOV     = $70 ;          FAC1 low order mantissa
-	!addr FBUFPT    = $71 ; $71-$72  -- NOT IMPLEMENTED --
+	!addr FBUFPT    = $71 ; $71-$72
+	!addr POLYPT    = FBUFPT
 	!addr CHRGET    = $73 ; $73-$8A  copied from $E3A2 during cold start
 	!addr CHRGOT    = $79 ; same area as CHRGET
 	!addr TXTPTR    = $7A ; $7A-$7B  current BASIC statement pointer

src/basic/math_trans/e043.poly1_FAC1.s

@@ -2,9 +2,13 @@
 ;; #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 - evaluate polynomial with odd powers only for FAC1 value
 ;
+; This is verified to be identical to the original Microsoft implementation where it was named POLYX.
+;
 ; Input:
 ; - .A - table address low byte
 ; - .Y - table address low byte
@@ -25,14 +29,15 @@
 
 
 poly1_FAC1:
-    jsr store_YA_in_ZP              ; Store YA in second INDEX pointer
-    jsr mov_r_FAC1_TMP1             ; TMPF1 <- FAC1  (rounds)
-    jsr mov_FAC1_FAC2               ; FAC2 <- FAC1
-    jsr mul_FAC2_FAC1               ; FAC1 <- FAC1 * FAC2  (x^2)
-    jsr poly2_table_in_index2       ; poly2: skip storing YA to ZP
-    ldy #$00                        ; FAC1 <- FAC1 * TEMPF1
-    lda #TEMPF1
-    jmp mul_MEM_FAC1
+        sta POLYPT            ; Retain polynomial pointer for later
+        sty POLYPT+1
+        jsr mov_r_FAC1_TMP1     ; Save FAC1 in TMP1
+        lda #TEMPF1
+        jsr mul_MEM_FAC1        ; Compute x^2
+        jsr POLY1               ; Compute P(x^2)
+        lda #<TEMPF1
+        ldy #>TEMPF1
+        jmp mul_MEM_FAC1        ; Multiply by FAC1 again
 
 
 } else {