duskos

commit 311c464ecb3f900c02bef592232fc8bcc55b125e
parent 1f7a1e549f7c55c219c3a22caaf3e7cba30c4a28
Author: Virgil Dupras <hsoft@hardcoded.net>
Date:   Thu, 30 Jun 2022 07:43:29 -0400

fs/boot: add directory entries buffer

Allows to search in more than 16 entries

Diffstat:
M
fs/fs/boot.fs
 | 
30
++++++++++++++++++++----------
M
fs/sys/drive.fs
 | 
4
++--
M
fs/tests/fs/boot.fs
 | 
5
++---

3 files changed, 24 insertions(+), 15 deletions(-)
diff --git a/fs/fs/boot.fs b/fs/fs/boot.fs
@@ -12,8 +12,8 @@
 
 $18 const BPBSZ \ we only care about a part of the BPB
 create bpb BPBSZ allot
+0 drv@ drvbuf( bpb BPBSZ move
 
-: fat16$ 0 drv@ drvbuf( bpb BPBSZ move ;
 : BPB_BytsPerSec bpb $0b + w@ ;
 : BPB_SecPerClus bpb $0d + c@ ;
 : BPB_RsvdSecCnt bpb $0e + w@ ;
@@ -28,18 +28,28 @@ create bpb BPBSZ allot
 : FirstRootDirSecNum BPB_RsvdSecCnt BPB_NumFATs BPB_FATSz16 * + ;
 
 32 const DIRENTRYSZ
-create fnbuf 11 allot
+\ A buffer where dir entries are copied before we search in them. It's big
+\ enough to hold the root dir entries. This means that no directory in the FS
+\ can have more than BPB_RootEntCnt entries.
+create dirbuf( RootDirSectors BPB_BytsPerSec * allot
+here const )dirbuf
+11 const FNAMESZ
+create fnbuf FNAMESZ allot
 
 : upcase ( c -- c ) dup 'a' - 26 < if $df and then ;
 \ we assume a 8.3 name. Don't call this with an inadequate name.
 : _tofnbuf ( fname -- )
-  A>r >A Ac@+ >r fnbuf 11 SPC fill fnbuf begin ( a )
+  A>r >A Ac@+ >r fnbuf FNAMESZ SPC fill fnbuf begin ( a )
     Ac@+ dup '.' = if ( a c ) 2drop fnbuf 8 + else upcase swap c!+ then
     next drop r>A ;
-\ Search in directory that is currently loaded in drvbuf.
-\ Return address of directory entry, or 0 if not found.
-\ TODO: support more than 1 sector dir entry
-: findindir ( fname -- ) _tofnbuf
-  16 >r drvbuf( begin ( a )
-    fnbuf over 11 []= if r~ exit then DIRENTRYSZ + next
-  abort" file not found" ;
+\ Search in directory that is currently loaded in dirbuf.
+\ Return address of directory entry, abort if not found.
+: findindir ( fname -- direntry ) _tofnbuf
+  dirbuf( begin ( a )
+    dup )dirbuf < while ( a )
+    fnbuf over FNAMESZ []= not while ( a ) DIRENTRYSZ + repeat
+    ( success ) else ( not found ) abort" file not found" then ( a ) ;
+
+\ Make the current dir the root
+: readroot A>r RootDirSectors >r FirstRootDirSecNum >A dirbuf( begin ( a )
+    A> over (drv@) A+ drvblksz + next ( a ) drop r>A ;
diff --git a/fs/sys/drive.fs b/fs/sys/drive.fs
@@ -29,8 +29,8 @@ alias abort (drv@)
 ( blkno buf -- )
 alias abort (drv!)
 
-: drv@ ( blkno -- ) dup to drvblksz drvbuf( (drv@) ;
-: ?drv@ ( blkno -- ) dup drvblksz = if drop else drv@ then ;
+: drv@ ( blkno -- ) dup to drvcurblk drvbuf( (drv@) ;
+: ?drv@ ( blkno -- ) dup drvcurblk = if drop else drv@ then ;
 
 \ Ensure that the block containing offset "off" (in bytes) is loaded and that
 \ there's at least u bytes following that offset that is present in the buffer.
diff --git a/fs/tests/fs/boot.fs b/fs/tests/fs/boot.fs
@@ -7,8 +7,7 @@
 ?f<< fs/boot.fs
 testbegin
 \ Tests for fs/boot
-fat16$
-FirstRootDirSecNum drv@
+readroot
 S" init.fs" findindir
-11 []>str S" INIT    FS " #s=
+FNAMESZ []>str S" INIT    FS " #s=
 testend