X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?a=blobdiff_plain;f=src%2Fboot%2Fboot2.s;h=7067a8f308c3f4520f494962fe2ca4ca1e83ddbc;hb=28d44c4b65b11f37ffd69a2b0227f14ca5c4f137;hp=719f37e99549e7dbc249344f83170e4dc4a631f8;hpb=77450ffb9190c6aa2a04bc23792a143b5886e459;p=bootcensus

diff --git a/src/boot/boot2.s b/src/boot/boot2.s
index 719f37e..7067a8f 100644
--- a/src/boot/boot2.s
+++ b/src/boot/boot2.s
@@ -763,6 +763,9 @@ rmidt:	.short 0x3ff
 
 saved_esp: .long 0
 saved_ebp: .long 0
+saved_eax: .long 0
+saved_es: .word 0
+saved_ds: .word 0
 
 	# drop back to unreal mode to call 16bit interrupt
 	.global int86
@@ -803,17 +806,24 @@ int86:
 	mov %ebp, saved_ebp
 	mov 12(%ebp), %esp
 	popal
+	popfw
+	pop %es
+	pop %ds
+	# ignore fs and gs for now, don't think I'm going to need them
 	mov saved_esp, %esp
 
+	# move to the real-mode stack, accessible from ss=0
+	# just in case the BIOS call screws up our unreal mode
+	mov $0x7be0, %esp
+
 	# call 16bit interrupt
 int_op:	int $0
 
-	mov saved_ebp, %ebp
-	mov 12(%ebp), %esp
-	add $34, %esp
-	pushfw
-	pushal
-	mov saved_esp, %esp
+	# save all registers that we'll clobber before having the
+	# chance to populate the int86regs structure
+	mov %eax, saved_eax
+	mov %ds, saved_ds
+	mov %es, saved_es
 
 	# re-enable protection
 	mov %cr0, %eax
@@ -830,6 +840,18 @@ int_op:	int $0
 	mov %ax, %ss
 	nop
 
+	mov saved_ebp, %ebp
+	mov 12(%ebp), %esp
+	add $38, %esp
+	mov saved_ds, %ax
+	pushw %ax
+	mov saved_es, %ax
+	pushw %ax
+	pushfw
+	mov saved_eax, %eax
+	pushal
+	mov saved_esp, %esp
+
 	# restore 32bit interrupt descriptor table
 	lidt (saved_idtr)
 	sti
@@ -841,3 +863,5 @@ int_op:	int $0
 	# buffer used by the track loader ... to load tracks.
 	.align 16
 buffer:
+	.global low_mem_buffer
+low_mem_buffer: