Merge pull request #78 from rikardn/POLY

Add poly1 and poly2

src/basic/,stubs_math/e059.poly2_FAC1.s

@@ -1,28 +0,0 @@
-;; #LAYOUT# STD *       #TAKE
-;; #LAYOUT# *   BASIC_0 #TAKE
-;; #LAYOUT# *   *       #IGNORE
-
-;
-; Math package - evaluate polynomial with odd and even powers for FAC1 value
-;
-; Input:
-; - .A - table address low byte
-; - .Y - table address low byte
-; - table format:
-;   - polynomial degree (8 bit integer)
-;   - oefficients (floats), starting from highest degree, times 1+degree
-;
-; Notes:
-; - uses Horner method
-;
-; See also:
-; - [CM64] Computes Mapping the Commodore 64 - page 207
-; - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
-; - https://www.c64-wiki.com/wiki/POLY1
-;
-
-; XXX provide implementation
-
-poly2_FAC1:
-
-	+STUB_IMPLEMENTATION

src/basic/math/e043.poly1_FAC1.s

@@ -19,10 +19,14 @@
 ; - [CM64] Computes Mapping the Commodore 64 - page 206
 ; - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
 ; - https://www.c64-wiki.com/wiki/POLY1
-;
 
-; XXX provide implementation
 
 poly1_FAC1:
-
-	+STUB_IMPLEMENTATION
+    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

src/basic/math/e059.poly2_FAC1.s

@@ -0,0 +1,69 @@
+;; #LAYOUT# STD *       #TAKE
+;; #LAYOUT# *   BASIC_0 #TAKE
+;; #LAYOUT# *   *       #IGNORE
+
+;
+; Math package - evaluate polynomial with odd and even powers for FAC1 value
+;
+; Input:
+; - .A - table address low byte
+; - .Y - table address low byte
+; - FAC1 - value of the independent variable
+; Outputs: FAC1 holds the calculated value
+; Clobbers: X, Y, A, FAC2, TEMPF2
+;
+; The polynomial table is formatted as:
+; First one byte represents the degree of the polynomial
+; Then comes an array of floating point number coefficients starting with the highest degree
+; Horner's method is used for the calculation.
+
+; See also:
+; - [CM64] Computes Mapping the Commodore 64 - page 207
+; - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
+; - https://www.c64-wiki.com/wiki/POLY1
+;
+
+
+poly2_FAC1:
+    jsr store_YA_in_ZP
+
+poly2_table_in_index2:  ; Called from poly1
+    ldy #$00            ; FAC1 -> TMPF2
+    ldx #TEMPF2
+    jsr mov_FAC1_MEM
+
+    ldx #$80            ; 0 -> FAC1
+    stx FAC1_exponent
+
+    ldx #0
+    lda (INDEX+2, x)    ; degree (degree+1 = num coeffs)
+    sta SGNFLG          ; number of terms register
+    inc INDEX+2
+    bcc @1
+    inc INDEX+3
+
+@1:
+    lda INDEX+2
+    ldy INDEX+3
+    jsr add_MEM_FAC1    ; Add with coefficient
+    ldy #$00
+    lda #TEMPF2
+    jsr mul_MEM_FAC1    ; Multiply with x
+
+    clc                 ; Add 5 to table pointer
+    lda #$05
+    adc INDEX+2
+    sta INDEX+2
+    bcc @2
+    inc INDEX+3
+
+@2:
+    dec SGNFLG
+    bpl @1
+    rts
+
+
+store_YA_in_ZP:     ; Used also by poly1
+    sty INDEX+3     ; Store YA in second INDEX pointer
+    sta INDEX+2
+    rts