Implement UTF16" to store UEFI-compatible string

[rrq/jonasforth.git] / impl.asm

diff --git a/impl.asm b/impl.asm
index c713036c82afb2743c45a547e4b315ac4bf41ba4..67d11b57ac02a3b7378c6f87d6b0276d39c91b19 100644 (file)
--- a/impl.asm
+++ b/impl.asm
@@ -1,16 +1,12 @@
-;; vim: syntax=fasm
-
-segment readable executable
+os_code_section
 
 macro printlen msg, len {
   push rsi
   add rsp, 8
 
-  mov rsi, msg
+  mov rcx, msg
   mov rdx, len
-  mov rax, 1
-  mov rdi, 1
-  syscall
+  call os_print_string
 
   sub rsp, 8
   pop rsi
@@ -25,12 +21,6 @@ macro print msg {
   printlen msg, msg#.len
 }
 
-macro exit code {
-  mov rax, $3C
-  mov rdi, code
-  syscall
-}
-
 struc string bytes {
   . db bytes
   .len = $ - .
@@ -77,58 +67,6 @@ find:
 .found:
   ret
 
-;; Read a word from standard input. Returns pointer to string containing word as
-;; well as length.
-;;
-;; Results:
-;;   * rdx = Length of string
-;;   * rdi = Pointer to string buffer
-;;
-;; Clobbers pretty much everything.
-read_word:
-.skip_whitespace:
-  ;; Read characters into .char_buffer until one of them is not whitespace.
-  mov rax, 0
-  mov rdi, 0
-  mov rsi, .char_buffer
-  mov rdx, 1
-  syscall
-
-  ;; We consider newlines and spaces to be whitespace.
-  cmp [.char_buffer], ' '
-  je .skip_whitespace
-  cmp [.char_buffer], $A
-  je .skip_whitespace
-
-.alpha:
-  ;; We got a character that wasn't whitespace. Now read the actual word.
-  mov [.length], 0
-
-.read_alpha:
-  mov al, [.char_buffer]
-  movzx rbx, [.length]
-  mov rsi, .buffer
-  add rsi, rbx
-  mov [rsi], al
-  inc [.length]
-
-  mov rax, 0
-  mov rdi, 0
-  mov rsi, .char_buffer
-  mov rdx, 1
-  syscall
-
-  cmp [.char_buffer], ' '
-  je .end
-  cmp [.char_buffer], $A
-  jne .read_alpha
-
-.end:
-  mov rdi, .buffer
-  movzx rdx, [.length]
-
-  ret
-
 ;; Read a word from a buffer. Returns the buffer without the word, as well as
 ;; the word that was read (including lengths).
 ;;
@@ -142,11 +80,44 @@ read_word:
 ;;   * rdi = Word buffer
 ;;   * rdx = Length of word buffer
 pop_word:
-  mov rdi, rsi
-  mov rdx, 10
+.skip_whitespace:
+  mov al, [rsi]
+  cmp al, ' '
+  je .got_whitespace
+  cmp al, $A
+  je .got_whitespace
+  jmp .alpha
+.got_whitespace:
+  ;; The buffer starts with whitespace; discard the first character from the buffer.
+  inc rsi
+  dec rcx
+  jmp .skip_whitespace
 
-  add rsi, 10
-  sub rcx, 10
+.alpha:
+  ;; We got a character that wasn't whitespace. Now read the actual word.
+  mov rdi, rsi ; This is where the word starts
+  mov rdx, 1   ; Length of word
+
+.read_alpha:
+  ;; Extract character from original buffer:
+  inc rsi
+  dec rcx
+
+  ;; When we hit whitespace, we are done with this word
+  mov al, [rsi]
+  cmp al, ' '
+  je .end
+  cmp al, $A
+  je .end
+
+  ;; It wasn't whitespace; add it to word buffer
+  inc rdx
+  jmp .read_alpha
+
+.end:
+  ;; Finally, we want to skip one whitespace character after the word.
+  inc rsi
+  dec rcx
 
   ret
 
@@ -210,18 +181,14 @@ parse_number:
   pop rdi
   printlen rdi, [.length]
   newline
-  exit 100
+  mov rax, 100
+  call os_terminate
 
-segment readable writable
+os_data_section
 
 find.search_length dq ?
 find.search_buffer dq ?
 
-read_word.max_size = $FF
-read_word.buffer rb read_word.max_size
-read_word.length db ?
-read_word.char_buffer db ?
-
 parse_number.length dq ?
 parse_number.error_msg string "Invalid number: "