Small improvements to irqentry_extrastack assembler.

Simplify the entry assembler slightly.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
diff --git a/src/romlayout.S b/src/romlayout.S
index 9de91a2..f6b7979 100644
--- a/src/romlayout.S
+++ b/src/romlayout.S
@@ -486,7 +486,6 @@
         popl %ecx
         movl %edx, 12(%eax)
         movl %esp, 16(%eax)
-        movzwl %sp, %esp
         movw %ss, 20(%eax)
 
         movw %ds, %dx           // Setup %ss/%esp and call function
@@ -528,12 +527,9 @@
         popl %ecx
         movw %es, BREGS_es(%eax)
         movl %esp, BREGS_size+0(%eax)
-        movzwl %sp, %esp
         movw %ss, BREGS_size+4(%eax)
-        movl (%esp), %edx
-        movl %edx, BREGS_code(%eax)
-        movw 4(%esp), %dx
-        movw %dx, BREGS_flags(%eax)
+        popl BREGS_code(%eax)
+        popw BREGS_flags(%eax)
 
         movw %ds, %dx           // Setup %ss/%esp and call function
         movw %dx, %ss
diff --git a/vgasrc/vgaentry.S b/vgasrc/vgaentry.S
index a5622b8..9854448 100644
--- a/vgasrc/vgaentry.S
+++ b/vgasrc/vgaentry.S
@@ -84,8 +84,7 @@
         cld
         pushw %ds               // Set %ds:%eax to space on ExtraStack
         pushl %eax
-        movzwl %cs:ExtraStackSeg, %eax
-        movl %eax, %ds
+        movw %cs:ExtraStackSeg, %ds
         movl $(CONFIG_VGA_EXTRA_STACK_SIZE-BREGS_size-8), %eax
         popl BREGS_eax(%eax)    // Backup registers
         popw BREGS_ds(%eax)