From bfb7b58b30681f5c421e838fdef3dbc358e80f1e Mon Sep 17 00:00:00 2001 From: Kevin O'Connor Date: Sat, 11 Oct 2014 13:27:16 -0400 Subject: Backup and restore a20 on call32_sloppy() Previously, the a20 line would always be enabled and left on after call32_sloppy(). The setting should really be backed up and restored on each call. Signed-off-by: Kevin O'Connor --- src/stacks.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'src/stacks.c') diff --git a/src/stacks.c b/src/stacks.c index 4b26d9f..6f40cbe 100644 --- a/src/stacks.c +++ b/src/stacks.c @@ -25,6 +25,7 @@ struct { u8 method; u8 cmosindex; + u8 a20; u16 ss, fs, gs; struct descloc_s gdt; } Call32Data VARLOW; @@ -174,6 +175,9 @@ call32_sloppy_prep(void) inb(PORT_CMOS_DATA); SET_LOW(Call32Data.cmosindex, cmosindex); + // Enable a20 and backup it's previous state + SET_LOW(Call32Data.a20, set_a20(1)); + // Backup ss/fs/gs and gdt SET_LOW(Call32Data.ss, GET_SEG(SS)); SET_LOW(Call32Data.fs, GET_SEG(FS)); @@ -201,6 +205,9 @@ call32_sloppy_post(void) SET_SEG(FS, GET_LOW(Call32Data.fs)); SET_SEG(GS, GET_LOW(Call32Data.gs)); + // Restore a20 + set_a20(GET_LOW(Call32Data.a20)); + // Restore cmos index register outb(GET_LOW(Call32Data.cmosindex), PORT_CMOS_INDEX); inb(PORT_CMOS_DATA); -- cgit v1.1