X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=Kernel%2Farch%2Fx86%2Fproc.asm;h=014cfed1cac482bce97c168e1c976cf7211cdf3f;hb=5473bdfc429d224c40e37ff7065a8dbad119fa1e;hp=74a25d46b18618c93a903a5d67c913d85fcef8b7;hpb=4c717bb526a0a7b1aa44ed7fc4f07a6b7da5d2f9;p=tpg%2Facess2.git

diff --git a/Kernel/arch/x86/proc.asm b/Kernel/arch/x86/proc.asm
index 74a25d46..014cfed1 100644
--- a/Kernel/arch/x86/proc.asm
+++ b/Kernel/arch/x86/proc.asm
@@ -55,11 +55,14 @@ SwitchTasks:
 	
 	; Old IP
 	mov eax, [esp+0x20+16]
+	test eax, eax
+	jz .nosave
 	mov DWORD [eax], .restore
 	; Old SP
 	mov eax, [esp+0x20+8]
 	mov [eax], esp
 
+.nosave:
 	mov ecx, [esp+0x20+12]	; New IP
 	mov eax, [esp+0x20+20]	; New CR3
 	mov esp, [esp+0x20+ 4]	; New SP
@@ -376,4 +379,4 @@ User_Syscall_Exit:
 	mov ebx, [esp+4]
 	int 0xAC
 
-; vim: ft=nasm, ts=8
+; vim: ft=nasm ts=8