Changeset 77 in xtideuniversalbios for trunk/XTIDE_Universal_BIOS/Src/Libraries/math.asm

Timestamp:

Jan 4, 2011, 10:53:15 PM (13 years ago)

Author:

krille_n_@…

google:author:

krille_n_@hotmail.com

Message:

Minor size optimizations plus a bug fix in print.asm in Print_IntSW (DI was left hanging on the stack if the parameter in AX was positive). Also a very minor speed optimization in keys.asm in Keys_Backspace.

File:

• trunk/XTIDE_Universal_BIOS/Src/Libraries/math.asm (modified) (4 diffs)

trunk/XTIDE_Universal_BIOS/Src/Libraries/math.asm

@@ -2 +2 @@
 ; Project name  :   Math library
 ; Created date  :   7.10.2009
-; Last update   :   1.1.2010
-; Author        :   Tomi Tilli
+; Last update   :   4.1.2011
+; Author        :   Tomi Tilli,
+;               :   Krister Nordvall (optimizations)
 ; Description   :   ASM library to for math related functions.      
 
@@ -122 +123 @@
 .RetZero:                       ; Return 0 in DX:AX
     xor     ax, ax
-    xor     dx, dx
+    cwd
     ret
 %endif
@@ -143 +144 @@
 ALIGN JUMP_ALIGN
 Math_DivDWbyW:
-    mov     bx, ax
-    mov     ax, dx
-    xor     dx, dx
+    xor     bx, bx
+    xchg    bx, ax
+    xchg    dx, ax
     div     cx
     xchg    ax, bx
@@ -171 +172 @@
     push    cx
     push    ax
-    mov     ax, cx              ; Copy divisor to AX
-    mov     cl, 10              ; Load 10 to CL
+    mov     al, 10              ; Load 10 to AL
+    xchg    cx, ax              ; AX = Divisor CL = 10
     div     cl                  ; AL = Divisor divided by 10
     inc     ax                  ; Increment to compensate new remainder