1 files changed, 82 insertions, 0 deletions
diff --git a/libc/msdos/intr.c b/libc/msdos/intr.c
new file mode 100644
index 0000000..22de042
--- /dev/null
+++ b/libc/msdos/intr.c
@@ -0,0 +1,82 @@
+
+struct REGPACK
+{
+   unsigned r_ax, r_bx, r_cx, r_dx;
+   unsigned r_bp, r_si, r_di, r_ds, r_es, r_flags;
+};
+
+/* DANGER DANGER -- Self modifying code! */
+
+#asm
+.text
+save_sp:
+  dw	0
+#endasm
+
+intr(intr, regs)
+int intr;
+struct REGPACK * regs;
+{
+#asm
+  mov	bx,sp
+  push	bp
+  push	si
+  push	di
+  push	es
+  push	ds
+
+  mov	ax,[bx+2]
+  seg	cs
+  mov	[intr_inst+1],al
+  seg	cs
+  mov	[save_sp],sp
+
+  mov	bx,[bx+4]
+
+  mov	ah,[bx+18]	! Flags low byte
+  sahf 
+
+  mov	ax,[bx]
+  push	[bx+2]
+  mov	cx,[bx+4]
+  mov	dx,[bx+6]
+  mov	bp,[bx+8]
+  mov	si,[bx+10]
+  mov	di,[bx+12]
+  mov	es,[bx+16]
+  mov	ds,[bx+14]
+  pop	bx
+
+intr_inst:
+  int	$FF		! Must be a real int .. consider protected mode.
+
+  seg	cs		! Could be SS as DS==SS
+  mov	sp,[save_sp]
+  seg	cs
+  mov	[save_sp],ds
+  pop	ds
+  push	[save_sp]
+
+  push	bx
+  mov	bx,sp
+  mov	bx,[bx+12]
+
+  mov	[bx],ax
+  pop	[bx+2]
+  mov	[bx+4],cx
+  mov	[bx+6],dx 
+  mov	[bx+8],bp
+  mov	[bx+10],si
+  mov	[bx+12],di
+  pop	[bx+14]
+  mov	[bx+16],es
+  pushf
+  pop	[bx+18]
+
+  pop	es
+  pop	di
+  pop	si
+  pop	bp
+  
+#endasm
+}