If an int 1587 call is made from an option rom, stay in bigreal mode.

Modify the int 1587 handler to check if the POST phase is still
running.  If it is, use bigreal mode segment limits so that the caller
remains in bigreal mode when the 1587 handler completes.  This helps
with SeaVGABIOS' use of "direct" framebuffer accesses (an option rom
may attempt to display text during its option rom execution which can
cause SeaVGABIOS to make the int 1587 calls).

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

1 files changed, 9 insertions, 0 deletions

diff --git a/src/misc.c b/src/misc.c
index 191e7070..67123557 100644
--- a/src/misc.c
+++ b/src/misc.c
@@ -14,6 +14,15 @@
 
 #define PORT_MATH_CLEAR        0x00f0
 
+// Indicator if POST phase has been started (and if it has completed).
+int HaveRunPost VARFSEG;
+
+int
+in_post(void)
+{
+    return GET_GLOBAL(HaveRunPost) == 1;
+}
+
 
 /****************************************************************
  * Misc 16bit ISRs