duskos

commit f8708cc8bb968349c0e030013212ac2cb723e773
parent 6bd1db337c748f2b4a21ec550025de9e818fd857
Author: Virgil Dupras <hsoft@hardcoded.net>
Date:   Tue,  4 Jul 2023 14:41:34 -0400

lib/alloc: alignment discipline

Diffstat:
M
fs/doc/lib/alloc.txt
 | 
4
++++
M
fs/lib/alloc.fs
 | 
6
+++---
M
fs/lib/arena.fs
 | 
4
++--
M
fs/lib/malloc.fs
 | 
2
+-

4 files changed, 10 insertions(+), 6 deletions(-)
diff --git a/fs/doc/lib/alloc.txt b/fs/doc/lib/alloc.txt
@@ -35,10 +35,14 @@ struct which provides a common API.
   available. If not, do its "thing" (rollover, create a new arena, etc.). Return
   the (still unallocated!) address of that memory.
 
+  That address is always aligned to 4 bytes.
+
 :allot ( n self -- a )
   allocate n bytes in the allocator and return the address of the allocated
   memory space.
 
+  That address is always aligned to 4 bytes.
+
 :move ( src u self -- a )
   allocate u bytes and copy the range "src u" into it. Then, return the
   allocated memory space.
diff --git a/fs/lib/alloc.fs b/fs/lib/alloc.fs
@@ -19,10 +19,10 @@ struct[ Allocator
   : :freesz dup :)buf swap ptr - ;
 
   : :ensure ( n self -- a )
-    dup :freesz rot < if dup :findspace tuck swap to ptr else ptr then ;
+    dup :freesz rot < if dup :findspace tuck swap align4 to ptr else ptr then ;
 
   : :allot ( n self -- a )
-    2dup :ensure rot> to+ ptr ;
+    2dup :ensure rot> align4 to+ ptr ;
 
   : :move ( src u self -- a )
     over swap :allot ( src u dst ) tuck >r move r> ;
@@ -35,7 +35,7 @@ struct[ Allocator
   : :[ ( size self -- ) :allot dup to _ptr to@! here to _here ;
   : :] ( self -- a )
     here over ptr > if abort" allocator :[ overflow" then
-    _here to@! here swap to ptr _ptr ;
+    _here to@! here swap align4 to ptr _ptr ;
   : :, ( n self -- a ) CELLSZ swap :allot tuck ! ;
   : :s, ( str self -- a ) swap c@+ rot :[]>str ;
 ]struct
diff --git a/fs/lib/arena.fs b/fs/lib/arena.fs
@@ -6,7 +6,7 @@ struct[ ArenaBuf
   sfield nextbuf
   SZ &+ buf
   : :)buf buf ARENASZ + ;
-  : :new ( -- buf ) herefree# here 0 , ARENASZ allot ;
+  : :new ( -- buf ) herefree# here# 0 , ARENASZ allot ;
   : :next dup nextbuf ?dup not if :new tuck swap to nextbuf else nip then ;
 ]struct
 
@@ -19,7 +19,7 @@ extends Allocator struct[ Arena
     dup current ArenaBuf :next ( self arenabuf )
     tuck swap to current ( arenabuf ) ArenaBuf buf ;
   : :new ( -- arena )
-    ArenaBuf :new here swap dup ( arena arenabuf )
+    ArenaBuf :new here# swap dup ( arena arenabuf )
     ArenaBuf buf ( ptr ) , ['] _)buf , ['] _findspace ,
     dup ( root ) , ( current ) , ;
   : :reset ( self -- )
diff --git a/fs/lib/malloc.fs b/fs/lib/malloc.fs
@@ -4,7 +4,7 @@ struct[ _Buf
   sfield used
   SZ &+ buf
   : :)buf bi buf | size + ;
-  : :new ( sz -- buf ) herefree# here 0 , over , 0 , swap allot ;
+  : :new ( sz -- buf ) herefree# here# 0 , over , 0 , swap allot ;
   \ Find an unused buffer with a size >= "sz".
   : :find ( sz self -- buf-or-0 ) swap >r \ V1=sz
     begin dup while ( buf )