duskos

commit 7bddfd4116ab4d4d15fc237b0ab24d72368d1b4d
parent f8d6d50226d7f379939f9b4a0e34dc7886414efd
Author: Virgil Dupras <hsoft@hardcoded.net>
Date:   Tue, 27 Jun 2023 14:34:15 -0400

lib/endian: add alignment guarantees and drop the High HAL

see doc/lib/endian.

Diffstat:
M
fs/doc/lib/endian.txt
 | 
7
++++++-
M
fs/fs/fat.fs
 | 
9
++++-----
M
fs/lib/endian.fs
 | 
48
+++++++++++++++---------------------------------

3 files changed, 25 insertions(+), 39 deletions(-)
diff --git a/fs/doc/lib/endian.txt b/fs/doc/lib/endian.txt
@@ -23,4 +23,9 @@ be!  n a --   Big-endian store
 Each of these words have a 16-bit variant, so they can be called with a "16b"
 modulator. They don't have a "8b" one because it makes no sense.
 
-These words are implemented in HAL, so they're fast.
+Additionally, these words can ignore alignment discipline because they are
+guaranteed to read and write byte by byte.
+
+The tradeoff is that these words are much slower than their native counterpart.
+This unit can't use the High HAL because it's a dependencies to assemblers,
+which themselves are dependencies to the High HAL.
diff --git a/fs/fs/fat.fs b/fs/fs/fat.fs
@@ -22,6 +22,7 @@
 ?f<< /fs/fatlo.fs
 ?f<< /lib/fmt.fs
 ?f<< /lib/str.fs
+?f<< /lib/endian.fs
 
 extends FSInfo struct[ FATInfo
   DirEntry NAMESZ 2 + const BUFSZ \ 1 for the '.' and 1 for len
@@ -166,22 +167,20 @@ create _FATTemplate
 ( BootSig ) $29 c, ( VolID ) 0 , ( VolLabel ) ," NONAME     "
 ( FilSysType ) ," FAT12   "
 
-: lew! ( n a -- ) \ w! that can write on odd addresses w/ alignment discipline
-  over 8 rshift over 1+ c! c! ;
 : newFAT12 ( drv -- )
   fatopts clustercnt 341 / 1+ >r \ V1=fatseccnt
   ( drv ) dup Drive secsz >r ( drv ) \ V2=secsz
   here# V2 0 fill
   _FATTemplate here $3e move ( drv )
-  V2 here $0b + lew!
+  V2 here $0b + 16b le!
   fatopts secpertrk here $18 + w!
   fatopts numheads here $1a + w!
   fatopts drvnum here $24 + c!
   fatopts secperclus here $0d + c!
   fatopts rsvdsec here $0e + w!
-  fatopts rootentsec DirEntry SZ * here $11 + lew!
+  fatopts rootentsec DirEntry SZ * here $11 + 16b le!
   fatopts clustercnt fatopts secperclus * fatopts rootentsec +
-  fatopts rsvdsec + V1 + dup here $13 + lew!
+  fatopts rsvdsec + V1 + dup here $13 + 16b le!
   ." TotSec " . nl>
   V1 here $16 + w!
   $aa55 here $1fe + w!
diff --git a/fs/lib/endian.fs b/fs/lib/endian.fs
@@ -1,36 +1,18 @@
 \ Endian-ness convenience words
-?f<< /asm/hal.fs
+\ We cannot use the High HAL because assemblers depend on this unit.
 
-$1234 here ! here c@ $34 = const LITTLE_ENDIAN?
+: le@ >r 8b to@+ V1 8b to@+ V1 8 lshift or
+      8b to@+ V1 16 lshift or 8b to@+ V1 24 lshift or rdrop ;
+:16b >r 8b to@+ V1 8b to@+ V1 8 lshift or rdrop ;
+: le! >r dup 8b to!+ V1 8 rshift dup 8b to!+ V1 8 rshift
+      dup 8b to!+ V1 8 rshift 8b to!+ V1 rdrop ;
+:16b >r dup 8b to!+ V1 8 rshift 8b to!+ V1 rdrop ;
+: le, here le! 4 allot ; :16b here 16b le! 2 allot ;
 
-alias @ le@ :16b 16b @ ;
-alias ! le! :16b 16b ! ;
-alias , le, :16b 16b , ;
-LITTLE_ENDIAN? not [if] abort" TODO" [then]
-
-alias @ be@ :16b 16b @ ;
-alias ! be! :16b 16b ! ;
-alias , be, :16b 16b , ;
-LITTLE_ENDIAN? [if]
-  code be@ ( a -- n )
-    W>A, A) 8b) @, 8 i) <<,
-    A) 1 +) 8b) |, 8 i) <<,
-    A) 2 +) 8b) |, 8 i) <<,
-    A) 3 +) 8b) |, exit,
-
-  code16b
-    W>A, A) 8b) @, 8 i) <<,
-    A) 1 +) 8b) |, exit,
-
-  code be! ( n a -- )
-    W>A, drop, A) 3 +) 8b) !, 8 i) >>,
-    A) 2 +) 8b) !, 8 i) >>,
-    A) 1 +) 8b) !, 8 i) >>,
-    A) 8b) !, drop, exit,
-
-  code16b
-    W>A, drop, A) 1 +) 8b) !, 8 i) >>,
-    A) 8b) !, drop, exit,
-
-  : be, here be! 4 allot ; :16b here 16b be! 2 allot ;
-[then]
+: be@ >r 8b to@+ V1 24 lshift 8b to@+ V1 16 lshift or
+      8b to@+ V1 8 lshift or 8b to@+ V1 or rdrop ;
+:16b >r 8b to@+ V1 8 lshift 8b to@+ V1 or rdrop ;
+: be! >r dup 24 rshift 8b to!+ V1 dup 16 rshift 8b to!+ V1
+      dup 8 rshift 8b to!+ V1 8b to!+ V1 rdrop ;
+:16b >r dup 8 rshift 8b to!+ V1 8b to!+ V1 rdrop ;
+: be, here be! 4 allot ; :16b here 16b be! 2 allot ;