floating point division works now

2020-03-21 16:35:55 +01:00
1 parent 922c881a23
commit a76b3e21b0
@@ -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

@@ -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

@@ -18,6 +18,7 @@ muldiv_RESHO_set_0:

 	rts

+
 muldiv_RESHO_01_add_A:

 	clc