Changeset 41654 in vbox

Timestamp:

Jun 11, 2012 3:15:09 PM (13 years ago)

Author:

vboxsync

Message:

BIOS: Do not save registers which do not need to be saved.

File:

• trunk/src/VBox/Devices/PC/BIOS-new/support.asm (modified) (8 diffs)

trunk/src/VBox/Devices/PC/BIOS-new/support.asm

@@ -86 +86 @@
                 push    edx
                 push    ecx
-                push    ebx
 
                 rol     eax, 16
@@ -98 +97 @@
                 mul     ecx                 ; eax * ecx -> edx:eax
 
-                pop     ebx
                 pop     ecx
 
@@ -115 +113 @@
 ; memset taking a far pointer.
 ;
+; cx, es may be modified; di is preserved
+;
 ; @returns  dx:ax unchanged.
 ; @param    dx:ax   Pointer to the memory.
@@ -121 +121 @@
 ;
 _fmemset_:
-                push    es
                 push    di
-                push    cx
-                pushf
 
                 mov     es, dx
@@ -132 +129 @@
                 xchg    al, bl
 
-                popf
-                pop     cx
                 pop     di
-                pop     es
                 ret
 
@@ -141 +135 @@
 ;;
 ; memset taking far pointers.
+;
+; cx, es may be modified; si, di are preserved
 ;
 ; @returns  dx:ax unchanged.
@@ -150 +146 @@
                 push    bp
                 mov     bp, sp
-                push    es
                 push    di
                 push    ds
                 push    si
-                push    cx
-                popf
 
                 mov     es, dx
@@ -164 +157 @@
                 rep     movsb
 
-                pushf
-                pop     cx
                 pop     si
                 pop     ds
                 pop     di
-                pop     es
                 leave
                 ret