+;; vim: syntax=fasm
+
segment readable executable
macro printlen msg, len {
ret
+;; Read a word from a buffer. Returns the buffer without the word, as well as
+;; the word that was read (including lengths).
+;;
+;; Inputs:
+;; * rsi = Input buffer
+;; * rcx = Length of buffer
+;;
+;; Outputs:
+;; * rsi = Updated buffer
+;; * rcx = Length of updated buffer
+;; * rdi = Word buffer
+;; * rdx = Length of word buffer
+pop_word:
+.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
+
+.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:
+
+ ret
+
;; Parses a string.
;;
;; Parameters: