X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=Kernel%2Farch%2Fx86%2Fproc.asm;h=014cfed1cac482bce97c168e1c976cf7211cdf3f;hb=5473bdfc429d224c40e37ff7065a8dbad119fa1e;hp=4e7d1604ac218217df778d2213a080c5bf7685e9;hpb=dcebc16c576aa98eb6a33047f4c4b2b69b30a1bc;p=tpg%2Facess2.git

diff --git a/Kernel/arch/x86/proc.asm b/Kernel/arch/x86/proc.asm
index 4e7d1604..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
@@ -162,8 +165,7 @@ SetAPICTimerCount:
 	pop es
 	pop ds
 	popa
-	add esp, 4	; CPU ID
-	; No Error code / int num
+	add esp, 8	; CPU ID / Error Code
 	iret
 %endif
 ; --------------
@@ -376,3 +378,5 @@ User_Syscall_Exit:
 	xor eax, eax
 	mov ebx, [esp+4]
 	int 0xAC
+
+; vim: ft=nasm ts=8