duskos

commit e078faf0039f9fdcb54093bab93ea797e1160fb0
parent a69056e53690671991c4774bd06cef6e6222a99f
Author: Virgil Dupras <hsoft@hardcoded.net>
Date:   Mon,  8 Aug 2022 12:13:59 -0400

fs/fat: assert that FAT and drive sector sizes match

Diffstat:
M
fs/doc/drive.txt
 | 
6
+++---
M
fs/fs/fat.fs
 | 
2
+-
M
fs/fs/fatlo.fs
 | 
3
++-
M
fs/xcomp/bootlo.fs
 | 
2
+-

4 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/fs/doc/drive.txt b/fs/doc/drive.txt
@@ -10,16 +10,16 @@ The drive API exposes the features of the underlying driver through a specific
 data structure, called a Drive, which is 12 bytes in length in the form of 3
 fields of 4 bytes:
 
-sectorsize
+drvsecsz
 drv@
 drv!
 
-sectorsize is an integer describing, in bytes, the size of sectors read and
+drvsecsz is an integer describing, in bytes, the size of sectors read and
 written by the driver. It's often 512 bytes.
 
 drv@ ( sec dst drv -- )
   Read sector "sec" in memory address "dst", which needs to be a buffer at least
-  "sectorsize" in size. "drv" is a pointer to a Drive structure.
+  "drvsecsz" in size. "drv" is a pointer to a Drive structure.
 
 drv! ( sec src drv -- )
   Write sector "sec" from memory address "src".
diff --git a/fs/fs/fat.fs b/fs/fs/fat.fs
@@ -77,7 +77,7 @@ $ffff const EOC
 \ write multiple sectors from buf
 : writesectors ( sec u buf -- )
   A>r swap >r swap >A begin ( buf )
-    A> over fatdrv drv! A+ fatdrv sectorsize + next ( buf ) drop r>A ;
+    A> over fatdrv drv! A+ fatdrv drvsecsz + next ( buf ) drop r>A ;
 
 : writecluster ( cluster src -- )
   over 2 - $fff6 > if abort" cluster out of range!" then
diff --git a/fs/fs/fatlo.fs b/fs/fs/fatlo.fs
@@ -15,10 +15,11 @@
 
 \ See fs/fat.fs for complete implementation details.
 
-\ TODO: assert that fatdrv's sector size is the same as in the FAT's BPB
 create bpb 0 here fatdrv drv@ $18 allot
 
 : BPB_BytsPerSec bpb $0b + w@ ;
+BPB_BytsPerSec fatdrv drvsecsz = not [if]
+  ." Drive sector size not matching drive!" abort [then]
 : BPB_SecPerClus bpb $0d + c@ ;
 : BPB_RsvdSecCnt bpb $0e + w@ ;
 : BPB_NumFATs bpb $10 + c@ ;
diff --git a/fs/xcomp/bootlo.fs b/fs/xcomp/bootlo.fs
@@ -161,7 +161,7 @@ alias noop [then]
 
 \ Drive API
 \ Anticipating lib/drive
-: sectorsize ( drv -- ) @ ;
+: drvsecsz ( drv -- ) @ ;
 : drv@ ( sec dst drv -- ) dup 4 + @ execute ;
 : drv! ( sec src drv -- ) dup 8 + @ execute ;