duskos

commit 69f29a79e6ce34a55c1fdb3449e8b2568d6452a1
parent 6483d9cd3ab8e8c8e7061cb0914a8125334ed827
Author: Virgil Dupras <hsoft@hardcoded.net>
Date:   Sat, 23 Jul 2022 08:26:54 -0400

i386: implement (alias) abort quit

I hit a strange I/O bug in mbr.fs: when I add to much comments (I think when
mbr.fs hits the $400 size mark), I get messed up results (mostly hang during
the build). It must be a bug in the FAT driver... TODO

Diffstat:
M
fs/xcomp/i386.fs
 | 
25
++++++++++++++++++++++---
M
fs/xcomp/pc/mbr.fs
 | 
3
+--

2 files changed, 23 insertions(+), 5 deletions(-)
diff --git a/fs/xcomp/i386.fs b/fs/xcomp/i386.fs
@@ -9,7 +9,10 @@
 
 0 to realmode
 0 value L1
+0 value lblmainalias
 $8000 to binstart \ This code lives at $8000.
+$6000 const RSTOP
+$8000 const PSTOP
 here to org
 forward16 jmp, to L1
 
@@ -28,14 +31,30 @@ xcode (val)
   BX pspush,
   ret,
 
+xcode (alias)
+  ax pop,
+  ax ax 0 d) mov, \ TODO: support ax 0 d) jmp,
+  ax jmp,
+
+xcode main
+  xwordlbl (alias) abs>rel call,
+  pc to lblmainalias 0 ,
+
+xcode quit
+  cld,
+  sp RSTOP i) mov,
+  xwordlbl main abs>rel call,
+
 xcode fooval
   xwordlbl (val) abs>rel call,
   $07690748 ,
 
-xcode mainloop
+xcode abort
   L1 forward!
-  bp $8000 i) mov,
-  sp $6000 i) mov,
+  bp PSTOP i) mov,
+  xwordlbl quit abs>rel jmp,
+
+pc lblmainalias pc>addr !
   xwordlbl fooval abs>rel call,
   AX pspop,
   $b8000 m) ax mov,
diff --git a/fs/xcomp/pc/mbr.fs b/fs/xcomp/pc/mbr.fs
@@ -11,8 +11,7 @@ forward8 jmp, to L1 \ bypass BPB
 $23 allot L1 forward!
 cli, cld, GDTADDR m) lgdt,
 ax $0003 i) mov, $10 int, \ video mode 80x25
-\ read sector 2 from boot floppy in memory at address $8000
-ax $0201 i) mov, bx $8000 i) mov, cx $0002 i) mov, dx $0000 i) mov,  $13 int,
+ax $0210 i) mov, bx $8000 i) mov, cx $0002 i) mov, dx $0000 i) mov,  $13 int,
 ax cr0 mov, ax 1 i) or, cr0 ax mov,
 $08 0 jmpfar, here org - binstart + here 4 - w! 0 to realmode
 \ initialize all segments