Advance on 8086 emulator

lib/fcbparse.asm

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+; Parse ASCIIZ string into FCB
+; IN	SI	ptr to filename
+;       BX	ptr to FCB
+fcb_parse:
+  push di
+  push ax
+  mov di, bx
+  xor ax, ax
+  stosb
+.cleanout:
+  push di
+  mov cx, 0x0A
+  mov al, 0x20
+  rep stosb
+  pop di
+.base_loop:
+  call .read
+  cmp al, 0x2E
+  je .ext_start
+  cmp al, 0x20
+  je .ret
+  stosb
+  jmp .base_loop
+.ext_start:
+  mov di, bx
+  add di, 9
+.ext_loop:
+  call .read
+  cmp al, 0x20
+  je .ret
+  stosb
+  jmp .ext_loop
+.read:
+  lodsb
+  test al, al
+  jz .eret
+  cmp al, 0x0D
+  je .eret
+  ret
+.eret:
+  dec si
+  pop ax
+.ret:
+  pop ax
+  pop di
+  ret