Flesh out getfssec

diff --git a/extlinux.asm b/extlinux.asm
index 0b08a1f..fd841c8 100644 (file)
--- a/extlinux.asm
+++ b/extlinux.asm
@@ -101,18 +101,8 @@ comboot_seg        equ real_mode_seg       ; COMBOOT image loading zone
 file_sector    resd 1                  ; Next linear sector to read
 file_left      resd 1                  ; Number of sectors left
 file_in_sec    resd 1                  ; Sector where inode lives
-file_in_off    resw 1                  ; 
-file_in_start  resw 1                  ; Offset to beginning of inode
-file_1i_sec    resd 1                  ; First sector of current ind block
-file_1i_off    resw 1                  ; Offset to next block ptr
+file_in_off    resw 1
                resw 1
-file_2i_sec    resd 1                  ; First sector of current dind block
-file_2i_off    resw 1                  ; Offset to next block ptr
-               resw 1
-file_3i_sec    resd 1                  ; First sector of current dind block
-file_3i_off    resw 1                  ; Offset to next block ptr
-               resw 1
-               resb 24
                endstruc
 
 %ifndef DEPEND
@@ -1009,13 +999,13 @@ unmangle_name:
 
 
 ;
-; getsector:   Convert a linear sector index in a file to a linear sector number
+; linsector:   Convert a linear sector index in a file to a linear sector number
 ;      EAX     -> linear sector number
 ;      DS:SI   -> open_file_t
 ;
 ;              Returns next sector number in EAX; CF on EOF (not an error!)
 ;
-nextsector:
+linsector:
                push gs
                push ebx
                push esi
@@ -1133,7 +1123,59 @@ nextsector:
 ;      All arguments are advanced to reflect data read.
 ;
 getfssec:
+               push ebp
+               push eax
+               push ebx
+               push edx
+.getfragment:
+               mov eax,[si]                    ; Current start index
+               mov ebx,eax
+               call linsector
+               push eax                        ; Fragment start sector
+               mov edx,eax
+               xor ebp,ebp                     ; Fragment sector count
+.getseccnt:
+               inc bp
+               dec cx
+               jz .do_read
+               xor eax,eax
+               mov ax,es
+               shl ax,4
+               add ax,bx                       ; Now DI = how far into 64K block we are
+               not ax                          ; Bytes left in 64K block
+               inc eax
+               shr eax,SECTOR_SHIFT            ; Sectors left in 64K block
+               cmp bp,ax
+               jnb .do_read                    ; Unless there is at least 1 more sector room...
+               inc ebx                         ; Sector index
+               inc edx                         ; Linearly next sector
+               mov eax,ebx
+               call nextsector
+               jc .do_read
+               cmp edx,eax
+               je .getseccnt
+.do_read:
+               pop eax                         ; Linear start sector
+               call getlinsecsr
+               lea eax,[eax+ebp-1]             ; This is the last sector actually read
+               shl bp,9
+               add bx,bp                       ; Adjust buffer pointer
+               call nextsector
+               jc .eof
+               mov edx,eax
+               and cx,cx
+               jnz .getfragment
+.done:
+               pop edx
+               pop ebx
+               pop eax
+               pop ebp
                ret
+.eof:
+               xor edx,edx
+               stc
+               jmp .done
+
 
 
 ; -----------------------------------------------------------------------------