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changeset 3268:647774d06c41

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Updated stack copy routines for level2 krn module for 6809 provided by L. Curtis Boyle.
author David Ladd <drencor-xeen@users.sourceforge.net>
date Fri, 15 Nov 2019 22:11:52 -0600
parents 024ad1d926fd
children 86f00c7593bc
files level2/modules/kernel/krn.asm
diffstat 1 files changed, 18 insertions(+), 13 deletions(-) [+]
line wrap: on
line diff
--- a/level2/modules/kernel/krn.asm	Wed Jul 17 01:14:55 2019 +0200
+++ b/level2/modules/kernel/krn.asm	Fri Nov 15 22:11:52 2019 -0600
@@ -21,6 +21,11 @@
 *  19r9    2004/07/12  Boisy G. Pitre
 * F$SRqMem now properly scans the DAT images of the system to update
 * the D.SysMem map.
+*
+*  19r10   2019/11/15  L. Curtis Boyle
+* Optimized register stack copies on 6809 in 3 spots (Loop5, RtiLoop & Looper)
+*   Saves over 70 cycles per system call that switches between user &
+*   system states
 
         nam     krn
         ttl     NitrOS-9 Level 2 Kernel
@@ -30,7 +35,7 @@
         ENDC
 
 * defines for customizations
-Revision        set     9       module revision
+Revision        set     10       module revision
 Edition set     19      module Edition
 Where   equ     $F000   absolute address of where Kernel starts in memory
 
@@ -644,9 +649,9 @@
         ldw     #R$Size         get size of register stack
         tfm     x+,y+           copy it
       ELSE
-        ldb     #R$Size
-Loop5   lda     ,x+
-        sta     ,y+
+        ldb     #R$Size/2
+Loop5   ldu     ,x++
+        stu     ,y++
         decb
         bne     Loop5
       ENDC
@@ -865,10 +870,10 @@
         ldu     #Where+SWIStack point to the stack
         tfm     u+,y+           move the stack from top of memory to user memory
       ELSE
-        ldb     #R$Size
+        ldb     #R$Size/2
         ldu     #Where+SWIStack point to the stack
-RtiLoop lda     ,u+
-        sta     ,y+
+RtiLoop ldx     ,u++
+        stx     ,y++
         decb
         bne     RtiLoop
       ENDC
@@ -1018,13 +1023,13 @@
         ldw     #R$Size         get the size of the stack
         tfm     u+,y+           move the stack to the top of memory
         ELSE
-        pshs    b
-        ldb     #R$Size
-Looper  lda     ,u+
-        sta     ,y+
-        decb
+        pshs    x
+        lda     #R$Size/2       Move stack to top of memory (A is reset in L0EB8, no need to preserve)
+Looper  ldx     ,u++
+        stx     ,y++
+        deca
         bne     Looper
-        puls    b
+        puls    x
         ENDC
         bra     L0EB8           and go from map type 1 to map type 0