floating point division works now

STATUS.md

@@ -203,9 +203,9 @@ Floating point mathematical routines - not official, but well known and broadly
 | `$BA8C`   | `mov_MEM_FAC2`         | DONE     |                                                    |
 | `$BA90`   | `get_FAC2_via_INDEX`   | NOT DONE |                                                    |
 | `$BAE2`   | `mul10_FAC1`           | DONE     |                                                    |
-| `$BAFE`   | `div10_FAC1_p`         | PARTIAL  | needs `div_FAC2_FAC1`                              |
-| `$BB0F`   | `div_MEM_FAC1`         | PARTIAL  | needs `div_FAC2_FAC1`                              |
-| `$BB12`   | `div_FAC2_FAC1`        | PARTIAL  | not tested yet                                     |
+| `$BAFE`   | `div10_FAC1_p`         | DONE     |                                                    |
+| `$BB0F`   | `div_MEM_FAC1`         | DONE     |                                                    |
+| `$BB12`   | `div_FAC2_FAC1`        | DONE     |                                                    |
 | `$BBA2`   | `mov_MEM_FAC1`         | DONE     |                                                    |
 | `$BBA6`   | `get_FAC2_via_INDEX`   | NOT DONE |                                                    |
 | `$BBC7`   | `mov_r_FAC1_TMP2`      | PARTIAL  | not fully tested yet                               |

c64/basic/math/bb12.div_FAC2_FAC1.s

@@ -22,8 +22,6 @@
 // - https://codebase64.org/doku.php?id=base:kernal_floating_point_mathematics
 //
 
-// XXX test this code
-
 div_FAC2_FAC1:
 
 	// 'Pamiętaj, cholero - nie dziel przez zero!' - ancient polish proverb
@@ -44,7 +42,7 @@ div_FAC2_FAC1:
 
 	// Subtract the exponents
 
-	lda #$62                            // correction for bias and FAC2 digits
+	lda #$A0                            // correction for bias and FAC2 digits
 	sta RESHO+0
 	lda #$00
 	sta RESHO+1
@@ -67,9 +65,7 @@ div_FAC2_FAC1:
 	sta FAC1_exponent
 
 	// Divide the mantissas
-
 	jsr div_FAC1_denorm
-
 	jsr muldiv_RESHO_set_0
 	jsr div_mantissas
 

c64/basic/math/div_FAC1_denorm.s

@@ -3,11 +3,9 @@
 // #LAYOUT# *   *       #IGNORE
 
 //
-// Math package - denormalize FAC1 mantissa and adapt its exponent accordingly
+// Math package - denormalize FAC1 mantissa and adapt its exponent accordingly for division
 //
 
-// XXX test this
-
 div_FAC1_denorm:
 
 	// Set FACOV to 0, no need for increased precision here
@@ -21,12 +19,12 @@ div_FAC1_denorm:
 	bne div_FAC1_denorm_by_bit         // branch if last byte of mantissa is non-zero
 
 	lda FAC1_exponent
-	cmp #$F8
-	bcs div_FAC1_denorm_by_bit         // branch if not suitable to increment exponent by 8
+	cmp #$08
+	bcc div_FAC1_denorm_by_bit         // branch if not suitable to increment exponent by 8
 
 	// Increment exponent
 
-	adc #$08                           // Carry already clear
+	sbc #$08                           // Carry already sec
 	sta FAC1_exponent
 
 	// Move mantissa bytes
@@ -49,12 +47,11 @@ div_FAC1_denorm_by_bit:
 	bne div_FAC1_denorm_done           // branch if lowest bit of mantissa is already 1
 
 	lda FAC1_exponent
-	cmp #$FF
 	beq div_FAC1_denorm_done           // branch if not suitable to decrement exponent
 
 	// Decrement exponent
 
-	inc FAC1_exponent
+	dec FAC1_exponent
 
 	// Move mantissa bits
 

c64/basic/math/muldiv_RESHO_helpers.s

@@ -18,6 +18,7 @@ muldiv_RESHO_set_0:
 
 	rts
 
+
 muldiv_RESHO_01_add_A:
 
 	clc