duskos

commit a949b562d342bb6ace67f324a29e97dcee4291a8
parent 3fc5769f387b188d35c2eac8223a3cfd290fb0ab
Author: Virgil Dupras <hsoft@hardcoded.net>
Date:   Sun, 24 Jul 2022 12:05:03 -0400

i386: add find

Diffstat:
M
fs/asm/i386.fs
 | 
3
++-
M
fs/xcomp/i386.fs
 | 
48
++++++++++++++++++++++++++++++++++++++++++++++--
M
fs/xcomp/pc/boot.fs
 | 
2
+-

3 files changed, 49 insertions(+), 4 deletions(-)
diff --git a/fs/asm/i386.fs b/fs/asm/i386.fs
@@ -157,7 +157,8 @@ ES _ es   SS _ ss   DS _ ds   FS _ fs   GS _ gs
 \ Inherent
 : op ( opcode -- ) doer c, does> ( a -- ) c@ c, asm$ ;
 $c3 op ret,        $90 op nop,         $fa op cli,         $fc op cld,
-$ac op lodsb,      $ad op lods,
+$ac op lodsb,      $ad op lods,        $a6 op cmpsb,       $a7 op cmps,
+$f3 op repz,       $f2 op repnz,
 
 \ Jumps and relative addresses
 \ i386 jumps and calls in their immediate modes are relative. We keep it that
diff --git a/fs/xcomp/i386.fs b/fs/xcomp/i386.fs
@@ -11,6 +11,7 @@
 
 0 to realmode
 0 value L1
+0 value L2
 0 value lblmainalias
 0 value lbltoptr
 0 value lbltoexec
@@ -18,6 +19,8 @@
 0 value lblin<
 0 value lblcurword
 0 value lblret \ label for whenever you need to return early
+0 value lblcurrent
+0 value lblemit
 $8000 to binstart \ This code lives at $8000.
 $6000 const RSTOP
 $8000 const PSTOP
@@ -137,10 +140,11 @@ xcode !
 
 pc $b8000 ,
 xcode emit \ temporary, this is going in /drv/pc
+  AX pspop,
+pc to lblemit
   di dup ( pc ) m) mov,
   dup ( pc ) m) inc,
   ( pc ) m) inc,
-  AX pspop,
   di 0 d) al mov,
   di 1 d) 7 i) mov,
   ret,
@@ -225,6 +229,43 @@ xcode word
   lblret abs>rel jnz,
   0 jmp, \ TODO add error message
 
+xcode current
+  xwordlbl (val) abs>rel call,
+  pc to lblcurrent 0 ,
+
+xcode find ( str -- word-or-0 ) pc lblcurrent pc>addr !
+  si bp 0 d) mov,
+  cx cx xor,
+  cl si 0 d) mov,
+  bp 0 d) inc,
+  dx lblcurrent m) mov,
+pc ( loop )
+  di dx mov,
+  di dec,
+  al di 0 d) mov,
+  al $3f i) and,    \ 3f instead of 7f? we reserve space for another flag.
+  al cl cmp,
+  forward jnz, to L1 ( skip1 )
+  \ same length
+  di 4 i) sub,
+  di cx sub,
+  si bp 0 d) mov,
+  repz, cmpsb,
+  forward jnz, to L2 ( skip2 )
+  \ same contents
+  bp 0 d) dx mov,
+  ret,
+L2 forward! ( skip2 )
+  cl al mov,
+L1 forward! ( skip1 )
+  dx 5 i) sub,
+  dx dx 0 d) mov,
+  dx dx test,
+  ( pc ) abs>rel jnz, ( loop )
+  \ not found
+  bp 0 d) 0 i) mov,
+  ret,
+
 pc lblmainalias pc>addr !
   xwordlbl (s) abs>rel call,
   6 c, ," Hello "
@@ -241,7 +282,10 @@ pc lblmainalias pc>addr !
   xwordlbl swap abs>rel call,
   xwordlbl c@ abs>rel call,
   xwordlbl rtype abs>rel call,
-  xwordlbl bye abs>rel call,
+  xwordlbl word abs>rel call,
+  xwordlbl find abs>rel call,
+  AX pspop,
+  ax call,
 
 pc lblbootptr pc>addr !
 xbindict orgifydict
diff --git a/fs/xcomp/pc/boot.fs b/fs/xcomp/pc/boot.fs
@@ -1,2 +1,2 @@
-World! dontprint
+World! bye