swtch saves callee-saved registers

swtch idles on per-CPU stack, not on calling process's stack
fix pipe bugs
usertest.c tests pipes, fork, exit, close

1 files changed, 38 insertions, 0 deletions

diff --git a/x86.h b/x86.h
index b905f83..7bc677f 100644
--- a/x86.h
+++ b/x86.h
@@ -244,6 +244,30 @@ read_esp(void)
         return esp;
 }
 
+static __inline uint32_t
+read_esi(void)
+{
+        uint32_t esi;
+        __asm __volatile("movl %%esi,%0" : "=r" (esi));
+        return esi;
+}
+
+static __inline uint32_t
+read_edi(void)
+{
+        uint32_t edi;
+        __asm __volatile("movl %%edi,%0" : "=r" (edi));
+        return edi;
+}
+
+static __inline uint32_t
+read_ebx(void)
+{
+        uint32_t ebx;
+        __asm __volatile("movl %%ebx,%0" : "=r" (ebx));
+        return ebx;
+}
+
 static __inline void
 cpuid(uint32_t info, uint32_t *eaxp, uint32_t *ebxp, uint32_t *ecxp, uint32_t *edxp)
 {
@@ -280,6 +304,20 @@ read_tsc(void)
         return tsc;
 }
 
+// disable interrupts
+static __inline void
+cli(void)
+{
+        __asm __volatile("cli");
+}
+
+// enable interrupts
+static __inline void
+sti(void)
+{
+        __asm __volatile("sti");
+}
+
 struct PushRegs {
     /* registers as pushed by pusha */
     uint32_t reg_edi;