---

yaml
---
r: 61392
b: refs/heads/master
c: 8c027ae
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 7ad37df02c529525c4ad19035359af89d2d2a5bd
+refs/heads/master: 8c027ae2dcfa7b9130941a2a743c735c1fee04ee

trunk/arch/i386/boot/tty.c

@@ -31,7 +31,7 @@ void __attribute__((section(".inittext"))) putchar(int ch)
 
 	/* int $0x10 is known to have bugs involving touching registers
 	   it shouldn't.  Be extra conservative... */
-	asm volatile("pushal; int $0x10; popal"
+	asm volatile("pushal; pushw %%ds; int $0x10; popw %%ds; popal"
 		     : : "b" (0x0007), "c" (0x0001), "a" (0x0e00|ch));
 }
 

trunk/arch/i386/boot/video.h

@@ -117,8 +117,15 @@ extern int graphic_mode;	/* Graphics mode with linear frame buffer */
  * int $0x10 is notorious for touching registers it shouldn't.
  * gcc doesn't like %ebp being clobbered, so define it as a push/pop
  * sequence here.
+ *
+ * A number of systems, including the original PC can clobber %bp in
+ * certain circumstances, like when scrolling.  There exists at least
+ * one Trident video card which could clobber DS under a set of
+ * circumstances that we are unlikely to encounter (scrolling when
+ * using an extended graphics mode of more than 800x600 pixels), but
+ * it's cheap insurance to deal with that here.
  */
-#define INT10 "pushl %%ebp; int $0x10; popl %%ebp"
+#define INT10 "pushl %%ebp; pushw %%ds; int $0x10; popw %%ds; popl %%ebp"
 
 /* Accessing VGA indexed registers */
 static inline u8 in_idx(u16 port, u8 index)