Rewrite 2015 - Day 1 in x64 assembly

.idea/cmake.xml

@@ -2,10 +2,8 @@
 <project version="4">
   <component name="CMakeSharedSettings">
     <configurations>
-      <configuration PROFILE_NAME="Debug x86" ENABLED="true" CONFIG_NAME="Debug" TOOLCHAIN_NAME="Visual Studio x86" />
-      <configuration PROFILE_NAME="Release x86" ENABLED="true" CONFIG_NAME="Release" TOOLCHAIN_NAME="Visual Studio x86" />
-      <configuration PROFILE_NAME="Debug x64" ENABLED="true" CONFIG_NAME="Debug" TOOLCHAIN_NAME="Visual Studio x64" />
-      <configuration PROFILE_NAME="Release x64" ENABLED="true" CONFIG_NAME="Release" TOOLCHAIN_NAME="Visual Studio x64" />
+      <configuration PROFILE_NAME="Debug" ENABLED="true" CONFIG_NAME="Debug" TOOLCHAIN_NAME="Visual Studio x64" />
+      <configuration PROFILE_NAME="Release" ENABLED="true" CONFIG_NAME="Release" TOOLCHAIN_NAME="Visual Studio x64" />
     </configurations>
   </component>
 </project>

.idea/runConfigurations/2015___Day_01.xml

@@ -1,5 +1,5 @@
 <component name="ProjectRunConfigurationManager">
-  <configuration default="false" name="2015 - Day 01" type="CMakeRunConfiguration" factoryName="Application" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" WORKING_DIR="file://$PROJECT_DIR$/2015/01" PASS_PARENT_ENVS_2="true" PROJECT_NAME="AOC" TARGET_NAME="AOC_2015_01" CONFIG_NAME="Debug x86" RUN_TARGET_PROJECT_NAME="AOC" RUN_TARGET_NAME="AOC_2015_01">
+  <configuration default="false" name="2015 - Day 01" type="CMakeRunConfiguration" factoryName="Application" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" WORKING_DIR="file://$PROJECT_DIR$/2015/01" PASS_PARENT_ENVS_2="true" PROJECT_NAME="AOC" TARGET_NAME="AOC_2015_01" CONFIG_NAME="Debug" RUN_TARGET_PROJECT_NAME="AOC" RUN_TARGET_NAME="AOC_2015_01">
     <method v="2">
       <option name="com.jetbrains.cidr.execution.CidrBuildBeforeRunTaskProvider$BuildBeforeRunTask" enabled="true" />
     </method>

.idea/runConfigurations/2015___Day_02.xml

@@ -0,0 +1,7 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="2015 - Day 02" type="CMakeRunConfiguration" factoryName="Application" REDIRECT_INPUT="false" ELEVATE="false" USE_EXTERNAL_CONSOLE="false" WORKING_DIR="file://$PROJECT_DIR$/2015/02" PASS_PARENT_ENVS_2="true" PROJECT_NAME="AOC" TARGET_NAME="AOC_2015_02" CONFIG_NAME="Debug" RUN_TARGET_PROJECT_NAME="AOC" RUN_TARGET_NAME="AOC_2015_02">
+    <method v="2">
+      <option name="com.jetbrains.cidr.execution.CidrBuildBeforeRunTaskProvider$BuildBeforeRunTask" enabled="true" />
+    </method>
+  </configuration>
+</component>

2015/.gitignore

@@ -1,4 +1,2 @@
-/cmake-build-debug-x86/
-/cmake-build-debug-x64/
-/cmake-build-release-x86/
-/cmake-build-release-x64/
+/cmake-build-debug/
+/cmake-build-release/

2015/01/main.asm

@@ -1,25 +1,29 @@
-bits 32
+bits 64
+default rel
 
 section .text
 
-extern _print
-global _entryPoint
+extern print
+global entryPoint
 
-_entryPoint:
-  enter 0,0
-  push ebx
-  push edi
+entryPoint:
+  push rbp
+  mov rbp, rsp
 
-  xor eax, eax         ; current floor
-  xor ebx, ebx         ; current instruction
-  xor ecx, ecx         ; instruction counter
-  mov edx, [ ebp + 8 ] ; instruction pointer
-  mov edi, -1          ; first entered basement (-1 = unset)
+  push rbx
+  push rdi
+  sub rsp, 32
+
+  mov rdx, rcx ; instruction pointer
+  xor rax, rax ; current floor
+  xor rbx, rbx ; current instruction
+  xor rcx, rcx ; instruction counter
+  mov rdi, -1  ; first entered basement (-1 = unset)
 
 .instructionLoop:
-  inc ecx         ; increment instruction counter
-  mov bl, [ edx ] ; bl = instructions[edx]
-  inc edx         ; increment instruction pointer
+  inc rcx                 ; increment instruction counter
+  movzx rbx, byte [ rdx ] ; bl = instructions[rdx]
+  inc rdx                 ; increment instruction pointer
 
   cmp bl, '('       ; left parenthesis...
   je .moveUpFloor   ; moves up a floor
@@ -28,36 +32,34 @@ _entryPoint:
   jmp .end          ; unknown character skips to the end
 
 .moveUpFloor:
-  inc eax
+  inc rax
   jmp .instructionLoop
 
 .moveDownFloor:
-  dec eax
-  cmp eax, -1 ; check if we entered the basement
+  dec rax
+  cmp rax, -1 ; check if we entered the basement
   je .onEnteredBasement
   jmp .instructionLoop
 
  .onEnteredBasement:
-  cmp edi, -1          ; check if firstEnteredBasement has not been set yet
+  cmp rdi, -1          ; check if firstEnteredBasement has not been set yet
   jne .instructionLoop ; if it was already set, go to next instruction
-  mov edi, ecx         ; set first entered basement to instruction counter
+  mov rdi, rcx         ; set first entered basement to instruction counter
   jmp .instructionLoop
 
 .end:
-  push eax
-  push dword print_final_floor
-  call _print
-  pop eax
-  pop eax
+  lea rcx, [ print_final_floor ]
+  mov rdx, rax
+  call print
 
-  push edi
-  push dword print_first_entered_basement
-  call _print
-  pop edi
-  pop edi
+  lea rcx, [ print_first_entered_basement ]
+  mov rdx, rdi
+  call print
+
+  add rsp, 32
+  pop rdi
+  pop rbx
 
-  pop edi
-  pop ebx
   leave
   ret
 

2015/02/CMakeLists.txt

@@ -0,0 +1,5 @@
+set(PROJECT_NAME AOC_2015_02)
+
+project(${PROJECT_NAME} C ASM_NASM)
+
+add_executable(${PROJECT_NAME} main.asm ../utils/main.c ../utils/file.h ../utils/benchmark.h)

2015/02/main.asm

@@ -0,0 +1,113 @@
+bits 64
+default rel
+
+section .text
+
+extern print
+global entryPoint
+
+entryPoint:
+  push rbp
+  mov rbp, rsp
+
+  push rbx
+  push r12
+  sub rsp, 32
+
+  ; rax = reserved for math
+  ; rdx = reserved for math
+
+  ; rbx = value of current character of input string
+  ; rcx = pointer to current character of input string
+  ; r8  = return value for nextNumber
+  ; r9  = first dimension
+  ; r10 = second dimension
+  ; r11 = third dimension
+  ; r12 = total wrapping paper required
+
+  xor rdx, rdx
+  xor r12, r12
+
+.nextLine:
+  call .nextNumber
+  mov r9, r8  ; save first dimension to r9
+  call .nextNumber
+  mov r10, r8 ; save second dimension to r10
+  call .nextNumber
+  mov r11, r8 ; save third dimension to r11
+
+.sort1:        ; initiate bubble sort of the three dimensions (possible configurations 123; 132; 213; 231; 312; 321)
+  cmp r9, r10  ; compare first pair of dimensions
+  jb .sort2    ; if they are already sorted, skip ahead (123; 132; 231)
+  xchg r9, r10 ; otherwise, swap the first pair (213->123; 312->132; 321->231)
+.sort2:
+  cmp r10, r11  ; compare last pair of dimensions
+  jb .sort3     ; if they are already sorted, skip ahead (123)
+  xchg r10, r11 ; otherwise, swap the last pair (132->123; 231->213)
+.sort3:
+  cmp r9, r10  ; compare first pair of dimensions again in case the smallest number started at the end and was moved to second position
+  jb .sortEnd  ; if they are already sorted, skip ahead (123)
+  xchg r9, r10 ; otherwise, swap the first pair (213->123)
+.sortEnd:      ; at this point, the dimensions are sorted from smallest to largest in registers r9, r10, r11
+
+  mov rax, 2
+  mul r9
+  mul r10
+  add r12, rax ; add 2 * dim1 * dim2
+
+  mov rax, 2
+  mul r9
+  mul r11
+  add r12, rax ; add 2 * dim1 * dim3
+
+  mov rax, 2
+  mul r10
+  mul r11
+  add r12, rax ; add 2 * dim2 * dim3
+
+  mov rax, r9
+  mul r10
+  add r12, rax ; add square area of smallest side
+
+  movzx rbx, byte [ rcx ] ; read current character
+  cmp bl, 0               ; if we have not reached end of string yet,
+  jne .nextLine           ; go read the next line
+
+  lea rcx, [ print_wrapping_paper ]
+  mov rdx, r12
+  call print
+
+  add rsp, 32
+  pop r12
+  pop rbx
+
+  leave
+  ret
+
+.nextNumber:
+  xor r8, r8 ; reset return value to zero
+
+.nextDigit:
+  movzx rbx, byte [ rcx ] ; read current character
+  inc rcx                 ; move to next character
+
+  cmp bl, '0'
+  jb .nonDigitCharacter
+  cmp bl, '9'
+  ja .nonDigitCharacter
+
+  mov rax, 10
+  mul r8      ; shift digit accumulator by one decimal place
+  mov r8, rax ; move multiplied result back to digit accumulator
+
+  sub rbx, '0' ; convert ASCII to digit
+  add r8, rbx  ; add digit to accumulator
+
+  jmp .nextDigit
+
+.nonDigitCharacter:
+  ret ; return from nextNumber calls
+
+section .data
+
+print_wrapping_paper: db `Wrapping paper required: %d\n`, 0

2015/CMakeLists.txt

@@ -4,8 +4,9 @@ project(AOC)
 
 enable_language(ASM_NASM)
 
-set(CMAKE_CXX_FLAGS  "${CMAKE_CXX_FLAGS} /W4 /WX")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W4 /WX")
 set(CMAKE_NASM_LINK_EXECUTABLE "ld <LINK_FLAGS> <OBJECTS> -o <TARGET> <LINK_LIBRARIES>")
 set(CAN_USE_ASSEMBLER TRUE)
 
 add_subdirectory(01)
+add_subdirectory(02)

README.md

@@ -12,11 +12,9 @@ The repository contains a Gradle project (`build.gradle.kts`) that sets up every
 
 The source code is in `main.kt`. The run configuration executes the `main()` method in this file.
 
-## NASM x86 / x64 Assembly
+## NASM x64 Assembly
 
-The repository contains a CMake project (`CMakeLists.txt`) in the respective year's folder, which sets up every day as a CMake subproject. You should be able to load the CMake project into [CLion](https://www.jetbrains.com/clion/), as long as you have two toolchains set up:
-- Visual Studio x86
-- Visual Studio x64
+The repository contains a CMake project (`CMakeLists.txt`) in the respective year's folder, which sets up every day as a CMake subproject. You should be able to load the CMake project into [CLion](https://www.jetbrains.com/clion/), as long as you have a toolchain named `Visual Studio x64` set to use the `amd64` architecture.
 
 The source code is in `main.c`, which is either in the puzzle's own folder, or in `utils` if no adjustments are needed. By default, `main.c` reads the whole input file into a buffer, and passes it as a parameter to the `entryPoint` function defined in `main.asm` which implements the logic and output of each puzzle.
 
@@ -31,7 +29,8 @@ The versions should not matter, but I used Visual Studio 2019 with `MSVC v142 (1
 
 | Year | Day | Language |
 |-----:|----:|----------|
-| 2015 |  01 | NASM x86 |
+| 2015 |  01 | NASM x64 |
+| 2015 |  02 | NASM x64 |
 | 2021 |  01 | Kotlin   |
 | 2021 |  02 | Kotlin   |
 | 2021 |  03 | Kotlin   |