;; -----------------------------------------------------------------------
;;
-;; Copyright 1994-2002 H. Peter Anvin - All Rights Reserved
+;; Copyright 1994-2007 H. Peter Anvin - All Rights Reserved
;;
;; This program is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;;
;; Simple file handling library (open, getc, ungetc)
;;
+;; WARNING: This interface uses the real_mode_seg/comboot_seg.
+;;
+
+MAX_GETC_LG2 equ 4 ; Max number of file nesting
+MAX_GETC equ (1 << MAX_GETC_LG2)
+bytes_per_getc_lg2 equ 16-MAX_GETC_LG2
+bytes_per_getc equ (1 << bytes_per_getc_lg2)
+secs_per_getc equ bytes_per_getc/SECTOR_SIZE
+MAX_UNGET equ 5 ; Max bytes that can be pushed back
+
+ struc getc_file
+gc_file resw 1 ; File pointer
+gc_bufbytes resw 1 ; Bytes left in buffer
+gc_bytes resd 1 ; Bytes left in file
+gc_bufdata resw 1 ; Pointer to data in buffer
+gc_unget_cnt resb 1 ; Character pushed back count
+gc_unget_buf resb MAX_UNGET ; Character pushed back buffer
+ endstruc
+getc_file_lg2 equ 4 ; Size of getc_file as a power of 2
+
+%ifndef DEPEND
+%if (getc_file_size != (1 << getc_file_lg2))
+%error "getc_file_size != (1 << getc_file_lg2)"
+%endif
+%endif
;
; open,getc: Load a file a character at a time for parsing in a manner
-; similar to the C library getc routine. Only one simultaneous
-; use is supported. Note: "open" trashes the trackbuf.
+; similar to the C library getc routine.
+; Up to MAX_GETC files can be open at the same time,
+; they are accessed in a stack-like fashion.
+;
+; All routines assume CS == DS.
;
; open: Input: mangled filename in DS:DI
; Output: ZF set on file not found or zero length
;
; openfd: Input: file handle in SI
-; Output: none
+; Output: ZF set on getc stack overflow
;
; getc: Output: CF set on end of file
; Character loaded in AL
;
+; close: Output: CF set if nothing open
+;
open:
call searchdir
jz openfd.ret
openfd:
- pushf
- mov [FBytes],ax
- mov [FBytes+2],dx
- mov eax,[FBytes]
- add eax,SECTOR_SIZE-1
- shr eax,SECTOR_SHIFT
- mov [FSectors],eax ; Number of sectors
- mov [FNextClust],si ; Cluster pointer
- mov ax,[EndOfGetCBuf] ; Pointer at end of buffer ->
- mov [FPtr],ax ; nothing loaded yet
- popf ; Restore no ZF
+ push bx
+
+ mov bx,[CurrentGetC]
+ sub bx,getc_file_size
+ cmp bx,GetCStack
+ jb .stack_full ; Excessive nesting
+ mov [CurrentGetC],bx
+
+ mov [bx+gc_file],si ; File pointer
+ mov [bx+gc_bytes],ax ; Bytes available
+ mov [bx+gc_bytes+2],dx
+ xor ax,ax
+ mov [bx+gc_bufbytes],ax ; Buffer empty
+ mov [bx+gc_unget_cnt],al ; ungetc buffer empty
+
+ inc ax ; ZF <- 0
+ pop bx
.ret: ret
+.stack_full:
+ call close_file
+ xor ax,ax ; ZF <- 1
+ pop bx
+ ret
+
getc:
- stc ; If we exit here -> EOF
- mov ecx,[FBytes]
- jecxz .ret
- mov si,[FPtr]
- cmp si,[EndOfGetCBuf]
- jb .loaded
- ; Buffer empty -- load another set
- mov ecx,[FSectors]
- cmp ecx,trackbufsize >> SECTOR_SHIFT
- jna .oksize
- mov ecx,trackbufsize >> SECTOR_SHIFT
-.oksize: sub [FSectors],ecx ; Reduce remaining clusters
- mov si,[FNextClust]
- push es ; ES may be != DS, save old ES
- push ds
+ push bx
+ push si
+ push di
+ push es
+
+ mov di,[CurrentGetC]
+ movzx bx,byte [di+gc_unget_cnt]
+ and bx,bx
+ jnz .have_unget
+
+ mov ax,real_mode_seg ; Borrow the real_mode_seg
+ mov es,ax
+.got_data:
+ sub word [di+gc_bufbytes],1
+ jc .get_data ; Was it zero already?
+ mov si,[di+gc_bufdata]
+ mov al,[es:si]
+ inc si
+ mov [di+gc_bufdata],si
+.done:
+ clc
+.ret:
pop es
- mov bx,getcbuf
+ pop di
+ pop si
+ pop bx
+ ret
+.have_unget:
+ dec bx
+ mov al,[di+bx+gc_unget_buf]
+ mov [di+gc_unget_cnt],bl
+ jmp .done
+
+.get_data:
+ pushad
+ ; Compute start of buffer
+ mov bx,di
+ sub bx,GetCStack
+ shl bx,bytes_per_getc_lg2-getc_file_lg2
+
+ mov [di+gc_bufdata],bx
+ mov si,[di+gc_file]
+ mov ecx,[di+gc_bytes]
+ jecxz .empty
+ cmp ecx,bytes_per_getc
+ jna .sizeok
+ mov ecx,bytes_per_getc
+.sizeok:
+ mov [di+gc_bufbytes],cx
+ sub [di+gc_bytes],ecx
+ add cx,SECTOR_SIZE-1
+ shr cx,SECTOR_SHIFT
+ call getfssec
+ mov [di+gc_file],si
+ popad
+ jmp .got_data
+
+.empty:
+ popad
+ stc
+ jmp .ret
+
+close:
push bx
- call getfssec ; Load a trackbuf full of data
- mov [FNextClust],si ; Store new next pointer
- pop si ; SI -> newly loaded data
- pop es ; Restore ES
-.loaded: lodsb ; Load a byte, increment SI
- mov [FPtr],si ; Update next byte pointer
- dec dword [FBytes] ; Update bytes left counter
- clc ; Not EOF
-.ret: ret
+ push si
+ mov bx,[CurrentGetC]
+ mov si,[bx+gc_file]
+ and si,si
+ jz .closed
+.closed:
+ call close_file
+ add bx,getc_file_size
+ mov [CurrentGetC],bx
+ pop si
+ pop bx
+ ret
;
; ungetc: Push a character (in AL) back into the getc buffer
-; Note: if more than one byte is pushed back, this may cause
-; bytes to be written below the getc buffer boundary. If there
-; is a risk for this to occur, the getcbuf base address should
-; be moved up.
+; Note: if more than MAX_UNGET bytes are pushed back, all
+; hell will break loose.
;
ungetc:
- mov si,[FPtr]
- dec si
- mov [si],al
- mov [FPtr],si
- inc dword [FBytes]
+ push di
+ push bx
+ mov di,[CurrentGetC]
+ movzx bx,[di+gc_unget_cnt]
+ mov [bx+di+gc_unget_buf],al
+ inc bx
+ mov [di+gc_unget_cnt],bl
+ pop bx
+ pop di
ret
;
; Return CF on error
; DS:SI points to first character after number
;
-; Syntaxes accepted: [-]dec, [-]0+oct, [-]0x+hex, val+K, val+M
+; Syntaxes accepted: [-]dec, [-]0+oct, [-]0x+hex, val+[KMG]
;
parseint:
push eax
call unhexchar
jc .km ; Not a (hex) digit
cmp al,cl
- jae .km ; Invalid for base
+ jae .km ; Invalid for base
imul ebx,ecx ; Multiply accumulated by base
add ebx,eax ; Add current digit
lodsb
je .isk
cmp al,'m'
je .ism
+ cmp al,'g'
+ je .isg
dec si ; Back up
.fini: and bp,bp
jz .ret ; CF=0!
ret
.err: stc
jmp short .ret
-.isk: shl ebx,10 ; x 2^10
- jmp short .done
-.ism: shl ebx,20 ; x 2^20
- jmp short .done
-
+.isg: shl ebx,10 ; * 2^30
+.ism: shl ebx,10 ; * 2^20
+.isk: shl ebx,10 ; * 2^10
+ jmp .fini
section .bss
alignb 4
NumBuf resb 15 ; Buffer to load number
NumBufEnd resb 1 ; Last byte in NumBuf
-FBytes resd 1 ; Number of bytes left in getc file
-FSectors resd 1 ; Number of sectors in getc file
-FNextClust resw 1 ; Pointer to next cluster in d:o
-FPtr resw 1 ; Pointer to next char in buffer
+
+GetCStack resb getc_file_size*MAX_GETC
+.end equ $
+
+ section .data
+CurrentGetC dw GetCStack.end ; GetCStack empty
;
; unhexchar: Convert a hexadecimal digit in AL to the equivalent number;
projects / platform / upstream / syslinux.git / commitdiff