Add int_FAC1

STATUS.md

@@ -238,7 +238,7 @@ Floating point mathematical routines - not official, but well known and broadly
 | `$BC58`   | `abs_FAC1`             | NOT DONE |                                                    |
 | `$BC5B`   | `FCOMP`                | DONE     |                                                    |
 | `$BC9B`   | `QINT`                 | NOT DONE | convert FAC1 to 32 bit signed integer              |
-| `$BCCC`   | `int_FAC1`             | NOT DONE |                                                    |
+| `$BCCC`   | `int_FAC1`             | DONE     |                                                    |
 | `$BCF3`   | `FIN`                  | NOT DONE | imports string to FAC1, ignores spaces             |
 | `$BD7E`   | `FINLOG`               | NOT DONE |                                                    |
 | `$BDDD`   | `FOUT`                 | NOT DONE | outputs FAC1 to string at $0100                    |

src/basic/,stubs_math/bccc.int_FAC1.s

@@ -1,19 +0,0 @@
-;; #LAYOUT# STD *       #TAKE
-;; #LAYOUT# X16 BASIC_0 #TAKE-OFFSET 2000
-;; #LAYOUT# *   BASIC_0 #TAKE
-;; #LAYOUT# *   *       #IGNORE
-
-;
-; Math package - rounds away the decimal to make an integer
-;
-; See also:
-; - [CM64] Computes Mapping the Commodore 64 - page 116
-; - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
-; - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
-;
-
-; XXX provide implementation
-
-int_FAC1:
-
-	+STUB_IMPLEMENTATION

src/basic/math/bccc.int_FAC1.jmp.s

@@ -0,0 +1,8 @@
+;; #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 int_FAC1

src/basic/math/int_FAC1.s

@@ -0,0 +1,65 @@
+;; #LAYOUT# STD *       #TAKE
+;; #LAYOUT# X16 BASIC_0 #TAKE-OFFSET 2000
+;; #LAYOUT# *   BASIC_0 #TAKE
+;; #LAYOUT# *   *       #IGNORE
+
+;
+; Math package - rounds away the decimal to make an integer
+;
+; See also:
+; - [CM64] Computes Mapping the Commodore 64 - page 116
+; - https://www.c64-wiki.com/wiki/Floating_point_arithmetic
+; - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
+;
+
+int_FAC1:
+
+    lda FAC1_exponent
+    cmp #$81
+    bcc int_FAC1_zero           ; exponent is 0 or lower so integer part is 0
+    cmp #$A0
+    bcs int_FAC1_out            ; exponent is 32 or larger so the entire mantissa is part of the integer
+
+    tax
+    and #$07                    ; low three bits of exponent is number of bits to keep
+    tay
+    
+    txa
+    lsr                         ; Bits 4-5 of exponent is how many full mantissa bytes to keep
+    lsr
+    lsr
+    and #$03
+    tax
+
+    lda #$FF                    ; Create bit mask for first mantissa byte to change
+@1: lsr
+    dey
+    bne @1
+    eor #$FF
+
+    and FAC1_mantissa,X
+    sta FAC1_mantissa,X
+    lda #0
+@2: inx
+    cpx #$4
+    bcs @3
+    sta FAC1_mantissa,X
+    bcc @2
+
+@3: lda FAC1_sign
+    bpl int_FAC1_out
+    lda #<const_ONE             ; If negative subtract one
+    ldy #>const_ONE
+    jsr sub_MEM_FAC1            ; FAC1 = 1 - FAC1
+    lda #$FF
+    sta FAC1_sign               ; FAC1 = FAC1 - 1
+    rts
+
+
+    ; FIXME: Do we need to set FACOV to 0?
+
+int_FAC1_zero:
+    lda #0
+    sta FAC1_exponent
+int_FAC1_out:
+    rts

strings/A590F004

@@ -0,0 +1,3 @@
+LDA $90 + BEQ $04
+
+Check well known kernal i/o status variable in zero page

strings/A9BCA0B920

@@ -0,0 +1,3 @@
+LDA #$BC + LDY #$B9 + JSR
+
+Load well known address of float constant 1.0 into Y:A and make call.

strings/A9BCA0B92050B8A9

@@ -0,0 +1,3 @@
+LDA #$BC + LDY #$B9 + JSR $B850 + LDA
+
+Load well known address of float constant 1.0 and call subtract float.

strings/C8B17A85

@@ -0,0 +1,3 @@
+INY + BCS $7A + STA
+
+loop fragment

strings/FF856660

@@ -0,0 +1,3 @@
+$FF + STA $66 + RTS
+
+Fragment of storing a negative value to FAC1 sign, which is a well knows address in the zero page.

testsuite/unit/math.vs

@@ -233,4 +233,87 @@ ret
 print "CHECK A==0"
 r
 
+print "TEST: int_FAC1 0.0"
+fill $61 $61 00
+r PC=$BCCC
+ret
+fill $1001 $1001 00
+print "COMPARE"
+compare $61 $61 $1001
+print "END"
+
+print "TEST: int_FAC1 1.0"
+fill $61 $66 81 80 00 00 00 00
+r PC=$BCCC
+ret
+fill $1001 $1006 81 80 00 00 00 00
+print "COMPARE"
+compare $61 $66 $1001
+print "END"
+
+print "TEST: int_FAC1 1.5"
+fill $61 $66 81 C0 00 00 00 00
+r PC=$BCCC
+ret
+fill $1001 $1006 81 80 00 00 00 00
+print "COMPARE"
+compare $61 $66 $1001
+print "END"
+
+print "TEST: int_FAC1 1.5"
+fill $61 $66 81 C0 00 00 00 00
+r PC=$BCCC
+ret
+fill $1001 $1006 81 80 00 00 00 00
+print "COMPARE"
+compare $61 $66 $1001
+print "END"
+
+print "TEST: int_FAC1 0.5"
+fill $61 $66 80 80 00 00 00 00
+r PC=$BCCC
+ret
+fill $1001 $1001 00
+print "COMPARE"
+compare $61 $61 $1001
+print "END"
+
+print "TEST: int_FAC1 4.00000006519258"
+fill $61 $66 83 80 00 00 23 00
+r PC=$BCCC
+ret
+fill $1001 $1006 83 80 00 00 00 00
+print "COMPARE"
+compare $61 $66 $1001
+print "END"
+
+print "TEST: int_FAC1 -4.00000006519258"
+fill $61 $66 83 80 00 00 23 FF
+r PC=$BCCC
+ret
+fill $1001 $1006 83 A0 00 00 00 FF
+print "COMPARE"
+compare $61 $66 $1001
+print "END"
+
+print "TEST: int_FAC1 4398016684.0"
+fill $61 $66 A1 83 12 34 56 00
+r PC=$BCCC
+ret
+fill $1001 $1006 A1 83 12 34 56 00
+print "COMPARE"
+compare $61 $66 $1001
+print "END"
+
+print "TEST: int_FAC1 134216.81774902344"
+fill $61 $66 92 83 12 34 56 00
+r PC=$BCCC
+ret
+fill $1001 $1006 92 83 12 00 00 00
+print "COMPARE"
+compare $61 $66 $1001
+print "END"
+
+
+
 q