better build script!

build.sh

@@ -1,8 +1,14 @@
+QUIET="false"
+CLEAN="false"
+
 assemble () {
   FILE="$1"
   PROGRAM_NAME="$2"
 
-  echo "Assembling $PROGRAM_NAME"
+  if [ "$QUIET" = "false" ]; then
+    echo "Assembling $PROGRAM_NAME"
+  fi
+
   nasm -g -F dwarf -f elf64 "$FILE" -o "./target/$PROGRAM_NAME.o" || return
 }
 
@@ -23,27 +29,58 @@ build () {
 
     assemble "$FILE" "$PROGRAM_NAME"
 
-    echo "Linking $PROGRAM_NAME"
+    if [ "$QUIET" = "false" ]; then
+      echo "Linking $PROGRAM_NAME"
+    fi
+
     ld.lld "./target/$PROGRAM_NAME.o" "./target/common.o" -o "./target/$PROGRAM_NAME"
 }
 
-
-if [ "$1" = "--clean" ]; then
+clean () {
+  if [ -d ./target ]; then
     rm -r target
-    exit
+  fi
+}
+
+for ARG in "$@" ; do
+
+  case $ARG in
+
+    "--clean")
+      CLEAN="true"
+      ;;
+
+    "--quiet" | "-q")
+      QUIET="true"
+      ;;
+
+    "--help")
+      cat << EOF
+self-made shitty build script
+
+Run to build all programs into the ./target directory
+
+Options:
+  --quiet, -q   | Don't output information
+  --clean       | Clean all build artifacts
+EOF
+      exit
+      ;;
+
+  esac
+done
+
+if [ "$CLEAN" = "true" ]; then
+  clean
+  exit
 fi
 
 if [ ! -d ./target ]; then
   mkdir ./target
 fi
 
-
 assemble "src/common.asm" "common"
 
-if [ "$#" -eq 0 ]; then
-  for FILE in ./src/*.asm ; do
-    build "$FILE"
-  done
-else
-  build "src/$1.asm"
-fi
+for FILE in ./src/*.asm ; do
+  build "$FILE"
+done

src/common.asm

@@ -1,4 +1,10 @@
           global     itoa
+          global     println_num
+
+          section   .data
+print_num_buf: times 64 db 0
+
+          section   .text
 
 ; itoa - converts an unsigned integer into its ascii representation
 ; inputs:
@@ -7,13 +13,9 @@
 ; outputs:
 ;   rax - 0: success, 1: error
 ;   rbx - the length
-
 MAX_SIZE EQU 1000000000
 START_DIVISOR EQU MAX_SIZE / 10
 ASCII_NUM EQU 48
-
-          section   .text
-
 itoa:
 ; r12: whether we are in the leading zeroes (bool)
 ; r11: buffer start
@@ -86,4 +88,25 @@ return_success:
 number_too_big:
           mov       rax, 1      ; return error code 1
           mov       rbx, 0      ; we've written nothing
+          ret
+
+ASCII_NEWLINE EQU 10
+
+; println_num
+; prints a number to stdout
+; inputs:
+;   rax - the number
+println_num:
+          mov       rbx, print_num_buf
+          call      itoa
+
+          ; add a trailing newline
+          mov       byte [print_num_buf + rbx], ASCII_NEWLINE
+          inc       rbx
+
+          mov       rdx, rbx             ; len
+          mov       rax, 1               ; write
+          mov       rdi, 1               ; stdout
+          mov       rsi, print_num_buf
+          syscall
           ret

src/wc.asm

@@ -1,21 +1,31 @@
           extern     itoa
+          extern     println_num
+
           global     _start
 
+IO_BUF_SIZE EQU 1024
+
           section   .data
-itoa_buf: times 100 db 0
+io_buf:   times IO_BUF_SIZE db 0
 
           section   .text
 _start:
-          mov       rax, 45354
-          mov       rbx, itoa_buf
-          call      itoa
+          ; r13 is the character counter
+          xor       r13, r13
 
-          mov       rdx, rbx
-          mov       rax, 1
-          mov       rdi, 1
-          mov       rsi, itoa_buf
+process:
+          mov       rax, 0
+          mov       rdi, 0              ; stdin
+          mov       rsi, io_buf
+          mov       rdx, IO_BUF_SIZE
           syscall
 
+          add       r13, rax
+
+count_and_print:
+          mov       rax, r13
+          call      println_num
+
           mov       rax, 60
           xor       rdi, rdi
           syscall