From 8c027ae2dcfa7b9130941a2a743c735c1fee04ee Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Mon, 16 Jul 2007 11:58:24 -0700 Subject: [x86 setup] Save/restore DS around invocations of INT 10h There exists at least one card, Trident TVGA8900CL (BIOS dated 1992/9/8) which clobbers DS when "scrolling in an SVGA text mode of more than 800x600 pixels." Although we are extremely unlikely to run into that situation, it is cheap insurance to save and restore DS, and it only adds a grand total of 50 bytes to the total output. Pointed out by Etienne Lorrain. Cc: Etienne Lorrain Signed-off-by: H. Peter Anvin --- arch/i386/boot/tty.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/i386/boot/tty.c') diff --git a/arch/i386/boot/tty.c b/arch/i386/boot/tty.c index a8db78736b02..9c668aad3515 100644 --- a/arch/i386/boot/tty.c +++ b/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)); } -- cgit v1.2.2