diff options
| author | bde <bde@FreeBSD.org> | 1996-03-08 07:27:52 +0000 |
|---|---|---|
| committer | bde <bde@FreeBSD.org> | 1996-03-08 07:27:52 +0000 |
| commit | 9acf1cecfc141db5d0fc49519e5b2ed71a4a5996 (patch) | |
| tree | 501d9c87ba51382584145934b227367cb4351304 | |
| parent | b149de385358aae454e84aaa2ae0182793af8c2b (diff) | |
| download | FreeBSD-src-9acf1cecfc141db5d0fc49519e5b2ed71a4a5996.zip FreeBSD-src-9acf1cecfc141db5d0fc49519e5b2ed71a4a5996.tar.gz | |
Saved 14 bytes by avoiding gas braindamage and 8 bytes by better
instruction selection, for a total of 16 bytes after padding. Whee.
| -rw-r--r-- | sys/i386/boot/biosboot/asm.S | 45 |
1 files changed, 22 insertions, 23 deletions
diff --git a/sys/i386/boot/biosboot/asm.S b/sys/i386/boot/biosboot/asm.S index 885a3a5..a29dd87 100644 --- a/sys/i386/boot/biosboot/asm.S +++ b/sys/i386/boot/biosboot/asm.S @@ -24,7 +24,7 @@ * the rights to redistribute these changes. * * from: Mach, Revision 2.2 92/04/04 11:34:13 rpd - * $Id: asm.S,v 1.7 1996/03/08 05:15:53 bde Exp $ + * $Id: asm.S,v 1.8 1996/03/08 05:43:46 bde Exp $ */ @@ -89,18 +89,18 @@ ENTRY(real_to_prot) */ data32 ljmp $0x18, $xprot - xprot: + /* * we are in USE32 mode now * set up the protected mode segment registers : DS, SS, ES, FS */ - mov $0x20, %eax - movw %ax, %ds - movw %ax, %ss - movw %ax, %es + movw $0x20, %ax /* data segment */ + mov %ax, %ds /* gas would waste a prefix byte for movw */ + mov %ax, %ss + mov %ax, %es movw $0x10, %ax /* flat segment */ - movw %ax, %fs + mov %ax, %fs #ifdef BDE_DEBUGGER /* load idtr so we can debug */ @@ -148,11 +148,11 @@ xreal: * we are in real mode now * set up the real mode segment registers : DS, SS, ES, FS */ - movw %cs, %ax - movw %ax, %ds - movw %ax, %ss - movw %ax, %es - movw %ax, %fs + mov %cs, %ax + mov %ax, %ds + mov %ax, %ss + mov %ax, %es + mov %ax, %fs #ifdef BDE_DEBUGGER /* load idtr so we can debug */ @@ -179,8 +179,8 @@ ENTRY(startprog) movl %esp, %eax /* Use eax as the old stack pointer */ /* convert the current stack to a 32 bit flat model */ - mov $0x10, %ebx - movw %bx, %ss + movw $0x10, %bx + mov %bx, %ss addl $(BOOTSEG<<4),%esp /* copy the arguments from the old stack to the new stack */ @@ -199,9 +199,9 @@ ENTRY(startprog) pushl 0x08(%eax) /* kernel entry address */ /* convert over the other data segs */ - mov $0x10, %ebx - movw %bx, %ds - movw %bx, %es + movw $0x10, %bx + mov %bx, %ds + mov %bx, %es /* convert the PC (and code seg) */ lret @@ -226,12 +226,12 @@ ENTRY(pbzero) cld /* set %es to point at the flat segment */ - mov $0x10, %eax - movw %ax, %es + movw $0x10, %ax + mov %ax, %es mov 0x8(%ebp), %edi /* destination */ mov 0xc(%ebp), %ecx /* count */ - mov $0x0, %eax /* value */ + xorl %eax, %eax /* value 0 */ rep stosb @@ -259,8 +259,8 @@ ENTRY(pcpy) cld /* set %es to point at the flat segment */ - mov $0x10, %eax - movw %ax, %es + movw $0x10, %ax + mov %ax, %es mov 0x8(%ebp), %esi /* source */ mov 0xc(%ebp), %edi /* destination */ @@ -276,4 +276,3 @@ ENTRY(pcpy) pop %ebp ret - |
