Moved remainder to global var

src/test/java/dk/camelot64/kickc/test/kc/division.kc

@@ -1,11 +1,13 @@
 // Binary division implementation
 
+// Remainder after signed 8 bit division
+byte rem8u =0;
 
 // Performs division on two 8 bit unsigned bytes
 // Returns dividend/divisor.
-// If remainder is non-null it will be set to the remainder.
+// The remainder will be set into the global variable rem8u
 // Implemented using simple binary division
-byte div8u(byte dividend, byte divisor, byte* remainder) {
+byte div8u(byte dividend, byte divisor) {
     byte rem = 0;
     byte quotient = 0;
     for( byte i : 0..7) {
@@ -20,7 +22,7 @@ byte div8u(byte dividend, byte divisor, byte* remainder) {
             rem = rem - divisor;
         }
     }
-    *remainder = rem;
+    rem8u = rem;
     return quotient;
 }
 
@@ -29,8 +31,10 @@ signed byte rem8s = 0;
 
 // Perform division on two signed 8-bit numbers
 // Returns dividend/divisor.
-// The remainder will be set into the global variable rem16u
+// The remainder will be set into the global variable rem8s.
 // Implemented using simple binary division
+// Follows the C99 standard by truncating toward zero on negative results.
+// See http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1124.pdf section 6.5.5
 signed byte div8s(signed byte dividend, signed byte divisor) {
     byte neg = 0;
     byte dividendb = 0;
@@ -47,8 +51,7 @@ signed byte div8s(signed byte dividend, signed byte divisor) {
     } else {
         divisorb = (byte)divisor;
     }
-    byte rem8u = 0;
+    byte resultb = div8u(dividendb, divisorb);
-    byte resultb = div8u(dividendb, divisorb, &rem8u);
     if(neg==0) {
         rem8s = (signed byte)rem8u;
         return (signed byte)resultb;

src/test/java/dk/camelot64/kickc/test/kc/test-division.kc

@@ -34,14 +34,14 @@ void test_8u() {
     for( byte i: 0..5 ) {
         byte dividend = dividends[i];
         byte divisor = divisors[i];
-        byte res = div8u(dividend, divisor, &rem);
+        byte res = div8u(dividend, divisor);
         print_byte(dividend);
         print_str(" / @");
         print_byte(divisor);
         print_str(" = @");
         print_byte(res);
         print_str(" @");
-        print_byte(rem);
+        print_byte(rem8u);
         print_ln();
     }
 }

src/test/java/dk/camelot64/kickc/test/ref/test-division.asm

@@ -4,6 +4,7 @@
   .label SCREEN = $400
   .label char_cursor = 8
   .label line_cursor = 3
+  .label rem8s = $e
   .label rem16u = $a
   jsr main
 main: {
@@ -220,12 +221,11 @@ div16u: {
     rts
 }
 test_8u: {
-    .label rem = $14
     .label dividend = 7
     .label divisor = $e
+    .label res = $f
     .label i = 2
     lda #0
-    sta rem
     sta i
   b1:
     ldy i
@@ -235,13 +235,9 @@ test_8u: {
     sta divisor
     lda dividend
     sta div8u.dividend
-    lda #<rem
-    sta div8u.remainder
-    lda #>rem
-    sta div8u.remainder+1
     jsr div8u
     lda div8u.return
-    tax
+    sta res
     lda line_cursor
     sta char_cursor
     lda line_cursor+1
@@ -260,15 +256,15 @@ test_8u: {
     lda #>str1
     sta print_str.str+1
     jsr print_str
-    stx print_byte.b
+    lda res
+    sta print_byte.b
     jsr print_byte
     lda #<str2
     sta print_str.str
     lda #>str2
     sta print_str.str+1
     jsr print_str
-    lda rem
+    stx print_byte.b
-    sta print_byte.b
     jsr print_byte
     jsr print_ln
     inc i
@@ -287,7 +283,6 @@ div8u: {
     .label quotient = $10
     .label return = $10
     .label divisor = $e
-    .label remainder = 5
     ldx #0
     txa
     sta quotient
@@ -316,14 +311,13 @@ div8u: {
     cpx #8
     bne b1
     tya
-    ldy #0
+    tax
-    sta (remainder),y
     rts
 }
 test_8s: {
     .label dividend = 7
-    .label divisor = $15
+    .label divisor = $14
-    .label res = $e
+    .label res = $f
     .label i = 2
     lda #<SCREEN
     sta line_cursor
@@ -334,6 +328,7 @@ test_8s: {
     lda #>SCREEN
     sta char_cursor+1
     lda #0
+    sta rem8s
     tax
     sta i
   b1:
@@ -368,7 +363,8 @@ test_8s: {
     lda #>str2
     sta print_str.str+1
     jsr print_str
-    stx print_sbyte.b
+    lda rem8s
+    sta print_sbyte.b
     jsr print_sbyte
     jsr print_ln
     inc i
@@ -406,7 +402,6 @@ print_sbyte: {
 }
 div8s: {
     .label neg = $11
-    .label rem8u = $16
     cmp #0
     bpl b16
     eor #$ff
@@ -427,29 +422,23 @@ div8s: {
     eor #1
     sta neg
   b4:
-    lda #0
-    sta rem8u
     sty div8u.dividend
     stx div8u.divisor
-    lda #<rem8u
-    sta div8u.remainder
-    lda #>rem8u
-    sta div8u.remainder+1
     jsr div8u
     lda div8u.return
     tay
     lda neg
     bne b5
     tya
-    ldx rem8u
+    stx rem8s
   breturn:
     rts
   b5:
-    lda rem8u
+    txa
     eor #$ff
     clc
     adc #1
-    tax
+    sta rem8s
     tya
     eor #$ff
     clc

src/test/java/dk/camelot64/kickc/test/ref/test-division.sym

@@ -11,9 +11,9 @@
 (byte*) char_cursor#104 char_cursor zp ZP_WORD:8 23.0
 (byte*) char_cursor#105 char_cursor zp ZP_WORD:8 17.333333333333332
 (byte*) char_cursor#109 char_cursor zp ZP_WORD:8 2.4444444444444446
-(byte*~) char_cursor#121 char_cursor zp ZP_WORD:8 22.0
+(byte*~) char_cursor#122 char_cursor zp ZP_WORD:8 22.0
-(byte*~) char_cursor#128 char_cursor zp ZP_WORD:8 22.0
+(byte*~) char_cursor#129 char_cursor zp ZP_WORD:8 22.0
-(byte*~) char_cursor#137 char_cursor zp ZP_WORD:8 22.0
+(byte*~) char_cursor#138 char_cursor zp ZP_WORD:8 22.0
 (byte*) char_cursor#14 char_cursor zp ZP_WORD:8 2.5227272727272725
 (byte*) char_cursor#64 char_cursor zp ZP_WORD:8 5.0
 (word()) div16u((word) div16u::dividend , (word) div16u::divisor)
@@ -64,21 +64,19 @@
 (signed byte) div8s::dividend
 (signed byte) div8s::dividend#0 reg byte a 5.0
 (byte) div8s::dividendb
-(byte) div8s::dividendb#3 reg byte y 0.75
+(byte) div8s::dividendb#3 reg byte y 0.8571428571428571
 (byte~) div8s::dividendb#7 reg byte y 4.0
 (byte~) div8s::dividendb#8 reg byte y 4.0
 (signed byte) div8s::divisor
 (signed byte) div8s::divisor#0 reg byte x 2.142857142857143
 (byte) div8s::divisorb
-(byte) div8s::divisorb#3 reg byte x 2.0
+(byte) div8s::divisorb#3 reg byte x 3.0
 (byte~) div8s::divisorb#4 reg byte x 4.0
 (byte~) div8s::divisorb#5 reg byte x 4.0
 (byte) div8s::neg
 (byte) div8s::neg#2 neg zp ZP_BYTE:17 2.0
 (byte) div8s::neg#3 neg zp ZP_BYTE:17 1.0
-(byte) div8s::neg#4 neg zp ZP_BYTE:17 0.8571428571428571
+(byte) div8s::neg#4 neg zp ZP_BYTE:17 1.0
-(byte) div8s::rem8u
-(byte) div8s::rem8u#0 rem8u zp ZP_BYTE:22 0.024390243902439025
 (byte) div8s::resultb
 (byte) div8s::resultb#0 reg byte y 0.6666666666666666
 (signed byte) div8s::return
@@ -86,7 +84,7 @@
 (signed byte) div8s::return#2 reg byte a 5.0
 (signed byte) div8s::return#3 reg byte a 22.0
 (signed byte~) div8s::return#6 reg byte a 2.0
-(byte()) div8u((byte) div8u::dividend , (byte) div8u::divisor , (byte*) div8u::remainder)
+(byte()) div8u((byte) div8u::dividend , (byte) div8u::divisor)
 (byte~) div8u::$1 reg byte a 202.0
 (label) div8u::@1
 (label) div8u::@2
@@ -119,8 +117,6 @@
 (byte) div8u::rem#4 reg byte y 202.0
 (byte) div8u::rem#5 reg byte y 101.0
 (byte) div8u::rem#8 reg byte y 101.66666666666667
-(byte*) div8u::remainder
-(byte*) div8u::remainder#8 remainder zp ZP_WORD:5 0.13333333333333333
 (byte) div8u::return
 (byte) div8u::return#0 return zp ZP_BYTE:16 45.142857142857146
 (byte) div8u::return#2 reg byte a 4.0
@@ -199,10 +195,13 @@
 (word) rem16u
 (word) rem16u#16 rem16u zp ZP_WORD:10 110.0
 (signed byte) rem8s
-(signed byte) rem8s#1 reg byte x 2.0
+(signed byte) rem8s#1 rem8s zp ZP_BYTE:14 2.0
-(signed byte) rem8s#18 reg byte x 110.0
+(signed byte) rem8s#18 rem8s zp ZP_BYTE:14 110.0
-(signed byte) rem8s#3 reg byte x 1.0833333333333333
+(signed byte) rem8s#3 rem8s zp ZP_BYTE:14 1.0833333333333333
-(signed byte~) rem8s#32 reg byte x 4.0
+(signed byte~) rem8s#32 rem8s zp ZP_BYTE:14 4.0
+(byte) rem8u
+(byte) rem8u#1 reg byte x 0.48
+(byte) rem8u#33 reg byte x 110.0
 (void()) test_16u()
 (label) test_16u::@1
 (label) test_16u::@10
@@ -249,14 +248,14 @@
 (signed byte[]) test_8s::dividends
 (const signed byte[]) test_8s::dividends#0 dividends = { (byte/signed byte/word/signed word/dword/signed dword) 127, -(byte/signed byte/word/signed word/dword/signed dword) 127, -(byte/signed byte/word/signed word/dword/signed dword) 127, (byte/signed byte/word/signed word/dword/signed dword) 127, (byte/signed byte/word/signed word/dword/signed dword) 127, (byte/signed byte/word/signed word/dword/signed dword) 127 }
 (signed byte) test_8s::divisor
-(signed byte) test_8s::divisor#0 divisor zp ZP_BYTE:21 3.3000000000000003
+(signed byte) test_8s::divisor#0 divisor zp ZP_BYTE:20 3.3000000000000003
 (signed byte[]) test_8s::divisors
 (const signed byte[]) test_8s::divisors#0 divisors = { (byte/signed byte/word/signed word/dword/signed dword) 5, (byte/signed byte/word/signed word/dword/signed dword) 7, -(byte/signed byte/word/signed word/dword/signed dword) 11, -(byte/signed byte/word/signed word/dword/signed dword) 13, (byte/signed byte/word/signed word/dword/signed dword) 17, (byte/signed byte/word/signed word/dword/signed dword) 19 }
 (byte) test_8s::i
 (byte) test_8s::i#1 i zp ZP_BYTE:2 11.0
 (byte) test_8s::i#10 i zp ZP_BYTE:2 1.8333333333333333
 (signed byte) test_8s::res
-(signed byte) test_8s::res#0 res zp ZP_BYTE:14 2.4444444444444446
+(signed byte) test_8s::res#0 res zp ZP_BYTE:15 2.4444444444444446
 (const string) test_8s::str str = (string) " / @"
 (const string) test_8s::str1 str1 = (string) " = @"
 (const string) test_8s::str2 str2 = (string) " @"
@@ -283,29 +282,27 @@
 (byte) test_8u::i
 (byte) test_8u::i#1 i zp ZP_BYTE:2 16.5
 (byte) test_8u::i#10 i zp ZP_BYTE:2 1.76
-(byte) test_8u::rem
-(byte) test_8u::rem#0 rem zp ZP_BYTE:20 0.12745098039215685
 (byte) test_8u::res
-(byte) test_8u::res#0 reg byte x 2.2
+(byte) test_8u::res#0 res zp ZP_BYTE:15 2.2
 (const string) test_8u::str str = (string) " / @"
 (const string) test_8u::str1 str1 = (string) " = @"
 (const string) test_8u::str2 str2 = (string) " @"
 
 zp ZP_BYTE:2 [ test_16u::i#10 test_16u::i#1 test_8u::i#10 test_8u::i#1 test_8s::i#10 test_8s::i#1 ]
 zp ZP_WORD:3 [ line_cursor#17 line_cursor#33 line_cursor#1 line_cursor#37 print_cls::sc#2 print_cls::sc#1 ]
-zp ZP_WORD:5 [ print_word::w#4 print_word::w#0 print_word::w#1 print_word::w#2 print_word::w#3 test_16u::dividend#0 print_str::str#10 print_str::str#12 print_str::str#0 div8u::remainder#8 ]
+zp ZP_WORD:5 [ print_word::w#4 print_word::w#0 print_word::w#1 print_word::w#2 print_word::w#3 test_16u::dividend#0 print_str::str#10 print_str::str#12 print_str::str#0 ]
 zp ZP_BYTE:7 [ print_byte::b#7 print_byte::b#9 print_byte::b#1 print_byte::b#2 print_byte::b#3 print_byte::b#4 print_byte::b#5 print_byte::b#6 print_sbyte::b#6 print_sbyte::b#5 print_sbyte::b#1 print_sbyte::b#2 print_sbyte::b#3 print_sbyte::b#4 print_sbyte::b#0 test_8u::dividend#0 test_8s::dividend#0 ]
 reg byte a [ print_char::ch#3 print_char::ch#1 print_char::ch#2 ]
-zp ZP_WORD:8 [ char_cursor#64 char_cursor#105 char_cursor#102 char_cursor#104 char_cursor#121 char_cursor#100 char_cursor#14 char_cursor#128 char_cursor#103 char_cursor#1 char_cursor#109 char_cursor#137 div16u::dividend#2 div16u::dividend#1 div16u::dividend#0 ]
+zp ZP_WORD:8 [ char_cursor#64 char_cursor#105 char_cursor#102 char_cursor#104 char_cursor#122 char_cursor#100 char_cursor#14 char_cursor#129 char_cursor#103 char_cursor#1 char_cursor#109 char_cursor#138 div16u::dividend#2 div16u::dividend#1 div16u::dividend#0 ]
 zp ZP_WORD:10 [ div16u::rem#4 rem16u#16 div16u::rem#8 div16u::rem#5 div16u::rem#1 div16u::rem#2 div16u::rem#3 ]
 zp ZP_WORD:12 [ div16u::quotient#3 div16u::return#0 div16u::quotient#1 div16u::quotient#2 div16u::return#2 test_16u::res#0 ]
 reg byte x [ div16u::i#2 div16u::i#1 ]
-zp ZP_BYTE:14 [ div8u::divisor#6 div8u::divisor#0 div8u::divisor#1 test_8u::divisor#0 test_8s::res#0 ]
+zp ZP_BYTE:14 [ div8u::divisor#6 div8u::divisor#0 div8u::divisor#1 test_8u::divisor#0 rem8s#18 rem8s#3 rem8s#32 rem8s#1 ]
 reg byte y [ div8u::rem#4 div8u::rem#8 div8u::rem#5 div8u::rem#1 div8u::rem#2 div8u::rem#3 ]
-zp ZP_BYTE:15 [ div8u::dividend#3 div8u::dividend#5 div8u::dividend#1 div8u::dividend#2 div8u::dividend#0 ]
+zp ZP_BYTE:15 [ div8u::dividend#3 div8u::dividend#5 div8u::dividend#1 div8u::dividend#2 div8u::dividend#0 test_8u::res#0 test_8s::res#0 ]
 zp ZP_BYTE:16 [ div8u::quotient#3 div8u::return#0 div8u::quotient#1 div8u::quotient#2 ]
 reg byte x [ div8u::i#2 div8u::i#1 ]
-reg byte x [ rem8s#18 rem8s#3 rem8s#32 rem8s#1 ]
+reg byte x [ rem8u#33 rem8u#1 ]
 reg byte y [ div8s::dividendb#3 div8s::dividendb#7 div8s::dividendb#8 ]
 reg byte x [ div8s::divisorb#3 div8s::divisorb#4 div8s::divisorb#5 ]
 zp ZP_BYTE:17 [ div8s::neg#4 div8s::neg#3 div8s::neg#2 ]
@@ -315,16 +312,13 @@ reg byte a [ print_byte::$0 ]
 reg byte a [ print_byte::$2 ]
 reg byte a [ div16u::$1 ]
 reg byte a [ div16u::$2 ]
-zp ZP_BYTE:20 [ test_8u::rem#0 ]
 reg byte a [ div8u::return#3 ]
-reg byte x [ test_8u::res#0 ]
 reg byte a [ div8u::$1 ]
-zp ZP_BYTE:21 [ test_8s::divisor#0 ]
+zp ZP_BYTE:20 [ test_8s::divisor#0 ]
 reg byte a [ div8s::dividend#0 ]
 reg byte x [ div8s::divisor#0 ]
 reg byte a [ div8s::return#3 ]
 reg byte a [ div8s::$2 ]
 reg byte x [ div8s::$7 ]
-zp ZP_BYTE:22 [ div8s::rem8u#0 ]
 reg byte a [ div8u::return#2 ]
 reg byte y [ div8s::resultb#0 ]