From 80469b4bfaf49a407d8d6b5bf3c2eb0d1c9870e6 Mon Sep 17 00:00:00 2001
From: Joe Zhao <ztuowen@gmail.com>
Date: Fri, 16 May 2014 17:12:37 +0800
Subject: Comments update

---
 rs422lib/sysctl.h | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

(limited to 'rs422lib/sysctl.h')

diff --git a/rs422lib/sysctl.h b/rs422lib/sysctl.h
index 11b65ed..b8301fa 100644
--- a/rs422lib/sysctl.h
+++ b/rs422lib/sysctl.h
@@ -12,6 +12,8 @@
 #ifndef SYSCTL_H_
 #define SYSCTL_H_
 
+// Sysctl priority bit
+// Lowest first
 #define SYS_BIT7 (0x80)
 #define SYS_BIT6 (0x40)
 #define SYS_BIT5 (0x20)
@@ -20,17 +22,34 @@
 #define SYS_BIT2 (0x04)
 #define SYS_BIT1 (0x02)
 #define SYS_BIT0 (0x01)
+
+// SYSCALL invocation routine
+// Used this in IRQ, also wakes up the cpu
 #define SYSCALL_IRQ(X) (syscall|=X,_BIC_SR_IRQ(CPUOFF))
+// Use this in anywhere other than IRQ
+// Continuous invocation ?
 #define SYSCALL(X) (syscall|=X)
 
+// Call handler type
+// Does't have any input
+// 	Preserve the state in other global variables
+//	Usage example -> rsbus_syscall()
 typedef void (*syshdlr)();
 
-void sysctl_reghdlr(unsigned int bit,syshdlr rot);// Always replace
+// Register call handler
+// Always replace old value
+void sysctl_reghdlr(unsigned int bit,syshdlr rot);
 
-void sysctl_rmhdlr(unsigned int bit);// Replace with something useless
+// Remove old call handler
+// Replace with something useless
+void sysctl_rmhdlr(unsigned int bit);
 
+// Insert it into mainloop
+// enabling automatic procedure invocation
 void sysroutine();
 
+// Setting up the proc base
+// Call before usage
 void sysctl_init();
 
 extern volatile unsigned char syscall;
-- 
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