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fox32rom: Don't crash when trying to open a file that doesn't exist

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Ry 2022-05-19 14:19:02 -07:00
parent 3583067b23
commit e18c466d34
1 changed files with 9 additions and 3 deletions
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12
ryfs.asm
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@ -12,11 +12,12 @@
; r1: disk ID ; r1: disk ID
; r2: file struct: pointer to a blank file struct ; r2: file struct: pointer to a blank file struct
; outputs: ; outputs:
; r0: first file sector ; r0: first file sector, or zero if file wasn't found
ryfs_open: ryfs_open:
push r1 push r1
push r2 push r2
push r10 push r10
push r31
; r10: pointer to file struct entry ; r10: pointer to file struct entry
mov r10, r2 mov r10, r2
@ -33,11 +34,15 @@ ryfs_open:
mov r1, TEMP_SECTOR_BUF mov r1, TEMP_SECTOR_BUF
add r1, 20 add r1, 20
mov r2, 11 ; compare 11 bytes mov r2, 11 ; compare 11 bytes
mov r31, 31 ; 31 file entries total
ryfs_open_find_dir_entry_loop: ryfs_open_find_dir_entry_loop:
call compare_memory_bytes call compare_memory_bytes
ifz jmp ryfs_open_found_dir_entry ifz jmp ryfs_open_found_dir_entry
add r1, 16 ; point to the file name in the next directory entry add r1, 16 ; point to the file name in the next directory entry
jmp ryfs_open_find_dir_entry_loop ; FIXME: this never returns if the file wasn't found loop ryfs_open_find_dir_entry_loop
; if we reach this point, the file wasn't found
mov r0, 0
jmp ryfs_open_end
ryfs_open_found_dir_entry: ryfs_open_found_dir_entry:
sub r1, 4 ; point to first sector of this file sub r1, 4 ; point to first sector of this file
mov.16 [r10], [r1] ; write file_first_sector mov.16 [r10], [r1] ; write file_first_sector
@ -46,7 +51,8 @@ ryfs_open_found_dir_entry:
inc r10 inc r10
mov.8 [r10], 0 ; write file_reserved mov.8 [r10], 0 ; write file_reserved
movz.16 r0, [r1] movz.16 r0, [r1]
ryfs_open_end:
pop r31
pop r10 pop r10
pop r2 pop r2
pop r1 pop r1