From fa2e2e3c81b2686229acc204ece380953a8031ea Mon Sep 17 00:00:00 2001
From: Robert Morris <rtm@csail.mit.edu>
Date: Fri, 26 Jul 2019 09:38:22 -0400
Subject: uservec before userret in trampoline, to match book and kernelvec

---
 kernel/kernelvec.S | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'kernel/kernelvec.S')

diff --git a/kernel/kernelvec.S b/kernel/kernelvec.S
index 9aabe96..222b172 100644
--- a/kernel/kernelvec.S
+++ b/kernel/kernelvec.S
@@ -8,8 +8,10 @@
 .globl kernelvec
 .align 4
 kernelvec:
+        // make room to save registers.
         addi sp, sp, -256
 
+        // save the registers.
         sd ra, 0(sp)
         sd sp, 8(sp)
         sd gp, 16(sp)
@@ -42,8 +44,10 @@ kernelvec:
         sd t5, 232(sp)
         sd t6, 240(sp)
 
+	// call the C trap handler in trap.c
         call kerneltrap
 
+        // restore registers.
         ld ra, 0(sp)
         ld sp, 8(sp)
         ld gp, 16(sp)
@@ -78,6 +82,7 @@ kernelvec:
 
         addi sp, sp, 256
 
+        // return to whatever we were doing in the kernel.
         sret
 
         #
-- 
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