X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?a=blobdiff_plain;f=src%2Fasmops.h;h=1f427679f6a662aac4a914bb8352b776d3340f95;hb=5e8cc93aaf1173688852acaa0825698c2dc0cb3f;hp=2578467a8c0abb1ee7db60b1ae81b580ca746b23;hpb=d1e8a437c1fab4535f82c4c214ec3330ac32e48d;p=bootcensus

diff --git a/src/asmops.h b/src/asmops.h
index 2578467..1f42767 100644
--- a/src/asmops.h
+++ b/src/asmops.h
@@ -1,3 +1,20 @@
+/*
+pcboot - bootable PC demo/game kernel
+Copyright (C) 2018  John Tsiombikas <nuclear@member.fsf.org>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY, without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
 #ifndef ASMOPS_H_
 #define ASMOPS_H_
 
@@ -7,6 +24,11 @@
 #define disable_intr() asm volatile("cli")
 #define halt_cpu() asm volatile("hlt")
 
+#define CALLER_EIP(eip) \
+	asm volatile( \
+		"mov (%%esp), %0\n\t" \
+		: "=a" ((uint32_t)eip))
+
 static inline uint8_t inb(uint16_t port)
 {
 	uint8_t res;
@@ -52,6 +74,7 @@ static inline uint32_t inl(uint16_t port)
 		"outl %0, %1\n\t" \
 		:: "a" ((uint32_t)(src)), "dN" ((uint16_t)(port)))
 
+/* delay for about 1us */
 #define iodelay() outb(0, 0x80)