4 files changed, 11 insertions, 7 deletions

diff --git a/src/fw/csm.c b/src/fw/csm.c
index 7cdb398f..aee2f90e 100644
--- a/src/fw/csm.c
+++ b/src/fw/csm.c
@@ -183,6 +183,7 @@ handle_csm_0002(struct bregs *regs)
     struct bios_data_area_s *bda = MAKE_FLATPTR(SEG_BDA, 0);
     bda->hdcount = 0;
 
+    thread_setup();
     mathcp_setup();
     timer_setup();
     clock_setup();
diff --git a/src/post.c b/src/post.c
index 6157b507..8cb7b7cb 100644
--- a/src/post.c
+++ b/src/post.c
@@ -124,7 +124,6 @@ interface_init(void)
     bda_init();
 
     // Other interfaces
-    thread_init();
     boot_init();
     bios32_init();
     pmm_init();
@@ -167,6 +166,7 @@ platform_hardware_setup(void)
 
     // Init base pc hardware.
     pic_setup();
+    thread_setup();
     mathcp_setup();
     timer_setup();
     clock_setup();
diff --git a/src/stacks.c b/src/stacks.c
index 1dbdfe9b..1ad9ef09 100644
--- a/src/stacks.c
+++ b/src/stacks.c
@@ -558,12 +558,13 @@ getCurThread(void)
     return (void*)ALIGN_DOWN(esp, THREADSTACKSIZE);
 }
 
-static int ThreadControl;
+static u8 CanInterrupt, ThreadControl;
 
 // Initialize the support for internal threads.
 void
-thread_init(void)
+thread_setup(void)
 {
+    CanInterrupt = 1;
     if (! CONFIG_THREADS)
         return;
     ThreadControl = romfile_loadint("etc/threads", 1);
@@ -673,11 +674,12 @@ void
 yield(void)
 {
     if (MODESEGMENT || !CONFIG_THREADS) {
-        check_irqs();
+        if (MODESEGMENT || CanInterrupt)
+            check_irqs();
         return;
     }
     struct thread_info *cur = getCurThread();
-    if (cur == &MainThread)
+    if (cur == &MainThread && CanInterrupt)
         // Permit irqs to fire
         check_irqs();
 
@@ -705,7 +707,8 @@ yield_toirq(void)
         yield();
         return;
     }
-    wait_irq();
+    if (MODESEGMENT || CanInterrupt)
+        wait_irq();
 }
 
 // Wait for all threads (other than the main thread) to complete.
diff --git a/src/stacks.h b/src/stacks.h
index 82c4c3c8..a3b031ce 100644
--- a/src/stacks.h
+++ b/src/stacks.h
@@ -28,7 +28,7 @@ extern struct thread_info MainThread;
 struct thread_info *getCurThread(void);
 void yield(void);
 void yield_toirq(void);
-void thread_init(void);
+void thread_setup(void);
 int threads_during_optionroms(void);
 void run_thread(void (*func)(void*), void *data);
 void wait_threads(void);