Implement binary search tree and base day1a on it

c64/btree.asm

@@ -0,0 +1,106 @@
+// vim: filetype=kickass
+
+.const next_index = $02
+.const input = $03
+// NOTE Assumes the tree is zeroed
+tree_insert:
+    ldx #0
+
+    !loop:
+        lda tree_values_lo, x
+        bne !not_zero+
+        lda tree_values_hi, x
+        bne !not_zero+
+
+            // Insert the node
+            lda input
+            sta tree_values_lo, x
+            lda input + 1
+            sta tree_values_hi, x
+
+            inc next_index
+            rts
+
+    !not_zero:
+        sec
+        lda tree_values_lo, x
+        sbc input
+        lda tree_values_hi, x
+        sbc input + 1
+        bcc !greater+
+
+        !less:
+            lda tree_left, x
+            bne !+
+                lda next_index
+                sta tree_left, x
+            !:
+            lda tree_left, x
+            tax
+
+            jmp !loop-
+
+        !greater:
+            lda tree_right, x
+            bne !+
+                lda next_index
+                sta tree_right, x
+            !:
+            lda tree_right, x
+            tax
+
+            jmp !loop-
+
+    brk
+
+
+tree_contains:
+    ldx #0
+
+    !loop:
+        sec
+        lda tree_values_lo, x
+        sbc input
+        beq !lo_eq+
+        lda tree_values_hi, x
+        sbc input + 1
+        bcc !greater+
+
+        !less:
+            lda tree_left, x
+            beq !not_found+
+            tax
+            jmp !loop-
+
+        !greater:
+            lda tree_right, x
+            beq !not_found+
+            tax
+            jmp !loop-
+
+        !not_found:
+            // Match not found, set 1 so bne branches
+            lda #1
+            rts
+
+        !lo_eq:
+            lda tree_values_hi, x
+            sbc input + 1
+            bne !less-
+
+            // Match found, set 0 so beq branches
+            lda #0
+            rts
+
+    brk
+
+
+    .align $100
+tree_values_lo:
+    .fill 256, 0
+tree_values_hi:
+    .fill 256, 0
+tree_left:
+    .fill 256, 0
+tree_right:
+    .fill 256, 0

c64/day01.asm

@@ -9,15 +9,13 @@
 // Destroys:
 //   a, x, y, $02..$04, $10..$1c, $20..$25, $fd..$fe, everything you've ever loved
 //
-.const input_pointer  = $03
-.const buffer_pointer = $20
-.const atoi_result    = $22
+.const input_pointer  = $20
+.const atoi_result    = $03  // Needs to be $03 for tree_insert
 
-.const outer_pointer  = $20
-.const inner_pointer  = $22
-.const remainder      = $24
+.const loop_pointer = $20
+.const remainder    = $24
 
-// Need to be $03 and $fd due to multiply_16bit_unsigned
+// Need to be $26 and $fd due to multiply_16bit_unsigned
 .const outer_value    = $26
 .const inner_value    = $fd
 
@@ -29,7 +27,6 @@ day01:
     // Parse the input at day01_input into an array of integers.
     //
     move_16_imm(input_pointer, day01_input)
-    move_16_imm(buffer_pointer, buffer)
     ldy #0
 
 !line:
@@ -64,26 +61,13 @@ day01:
     jmp !digit-
 
 !newline:
-    sty zp_temp
+    // Insert the converted number into the tree.
+    jsr tree_insert
 
-    // Append the result of the conversion to the array.
-    ldy #0
-    lda atoi_result + 0
-    sta (buffer_pointer), y
-
-    iny
-    lda atoi_result + 1
-    sta (buffer_pointer), y
-
-    // Increment the buffer pointer by 2.
-    lda #2
-    i16_i8_add_a(buffer_pointer)
-
-    ldy zp_temp
     iny
     bne !+
-    inc input_pointer + 1
-!:
+        inc input_pointer + 1
+    !:
 
     // Check for the null terminator.
     lda (input_pointer), y
@@ -92,60 +76,28 @@ day01:
     move_16_imm($03, str_parse_done)
     jsr write_string
 
-    move_16_imm(outer_pointer, buffer)
-
-    // Add every number to every other number
-!outer:
-    move_16_imm(inner_pointer, buffer)
-
-    // $03..$04 = buffer[i]
     ldy #0
-    lda (outer_pointer), y
-    sta outer_value
-    iny
-    lda (outer_pointer), y
-    sta outer_value + 1
+    !loop:
+        // Subtract the number from 2020 to find the needed value.
+        lda tree_values_lo, y
+        sta $fd
+        eor #$ff
+        sec
+        adc #<2020
+        sta $03
+        sta $26
 
-    dey
-    lda (outer_pointer), y
-    bne !not_zero+
-    iny
-    lda (outer_pointer), y
-    bne !not_zero+
-    jmp !error+
-!not_zero:
+        lda tree_values_hi, y
+        sta $fe
+        eor #$ff
+        adc #>2020
+        sta $04
+        sta $27
 
-    // Subtract from 2020 to see what number we need
-    i16_imm_i16_sub(remainder, 2020, outer_value)
+        iny
+        jsr tree_contains
+        bne !loop-
 
-!inner:
-    // $fd..$fe = buffer[j]
-    ldy #0
-    lda (inner_pointer), y
-    sta inner_value
-    iny
-    lda (inner_pointer), y
-    sta inner_value + 1
-
-    dey
-    lda (inner_pointer), y
-    bne !not_zero+
-    iny
-    lda (inner_pointer), y
-    bne !not_zero+
-
-    i16_inc(outer_pointer)
-    jmp !outer-
-
-!not_zero:
-    // j++
-    lda #2
-    i16_i8_add_a(inner_pointer)
-
-    // Continue the loop if the number didn't match the needed number.
-    i16_i16_cmp_bne(remainder, inner_value, !inner-)
-
-!done:
     // Multiply the results together
     sec
     jsr multiply_16bit_unsigned

c64/main.asm

@@ -4,7 +4,7 @@
 
     BasicUpstart2(main)
 
-* = $0900 "Main program"
+* = $1000 "Main program"
 .const SCREEN_RAM = $0400
 .const COLOR_RAM = $d800
 
@@ -43,6 +43,77 @@
         sta dst + i
     }
 }
+
+test_tree:
+    move_16_imm($03, !str_test+)
+    jsr write_string
+
+    move_16_imm($03, $10)
+    jsr tree_insert
+    move_16_imm($03, $08)
+    jsr tree_insert
+    move_16_imm($03, $04)
+    jsr tree_insert
+    move_16_imm($03, $12)
+    jsr tree_insert
+    move_16_imm($03, $1337)
+    jsr tree_insert
+
+
+    move_16_imm($03, $08)
+    jsr tree_contains
+    bne !fail+
+
+    move_16_imm($03, $13)
+    jsr tree_contains
+    beq !fail+
+
+    move_16_imm($03, $12)
+    jsr tree_contains
+    bne !fail+
+
+    move_16_imm($03, $1337)
+    jsr tree_contains
+    bne !fail+
+
+    move_16_imm($03, $0420)
+    jsr tree_contains
+    beq !fail+
+
+    move_16_imm($03, !str_success+)
+    jsr write_string
+
+    rts
+
+!fail:
+    u16_u16_move($10, $03)
+
+    move_16_imm($03, !str_fail+)
+    jsr write_string
+
+    lda $11
+    jsr print_hex_0x
+    lda $10
+    jsr print_hex
+    jsr print_newline
+
+    rts
+
+!str_test:
+    .text "[  ] test-tree"
+    .byte '\r', 0
+
+!str_fail:
+    .text "[!!]"
+    .byte '\n'
+    .text "Failed: "
+    .byte 0
+
+!str_success:
+    .text "[OK]"
+    .byte '\n', 0
+
+
 //
 // main
 //
@@ -55,21 +126,19 @@ main:
     sta $01
 
     jsr generate_multiplication_tables
+    //jsr test_tree
+
 
     jsr day01
 
-
 !loop:
     jmp !loop-
 
 
-buffer:
-    .fill $0400, 0
-
-
 #import "day01.asm"
 #import "screen.asm"
 #import "math.asm"
+#import "btree.asm"
 
 * = *     "Day 01 Input"
 day01_input: