[project @ 1998-12-15 09:41:57 by simonm]

add missing file from the merge.  The ghc-4-01 tag will be added.

ghc/rts/StgRun.S

+/* -----------------------------------------------------------------------------
+ * $Id: StgRun.S,v 1.2 1998/12/15 09:41:57 simonm Exp $
+ *
+ * Tiny assembler 'layer' between the C and STG worlds.
+ * 
+ * To run an STG function from C land, call
+ *
+ *		rv = StgRun(f);
+ *
+ * where "f" is the STG function to call.
+ *
+ * In the end, "f" must JMP to StgReturn (defined below),
+ * passing the return-value "rv" in R1,
+ * to return to the caller of StgRun returning "rv" in
+ * the whatever way C returns a value.
+ *
+ * NOTE: StgRun/StgReturn do *NOT* load or store Hp or any
+ * other registers (other than saving the C callee-saves 
+ * registers).  Instead, the called function "f" must do that
+ * in STG land.
+ * -------------------------------------------------------------------------- */
+
+#include "config.h"
+#include "Constants.h"	
+
+#ifndef USE_MINIINTERPRETER
+	
+/* 
+ * GCC will have assumed that pushing/popping of C-stack frames is
+ * going on when it generated its code, and used stack space
+ * accordingly.  However, we actually {\em post-process away} all
+ * such stack-framery (see \tr{ghc/driver/ghc-asm.lprl}). Things will
+ * be OK however, if we initially make sure there are
+ * @RESERVED_C_STACK_BYTES@ on the C-stack to begin with, for local
+ * variables.  
+ */
+
+/* -----------------------------------------------------------------------------
+   x86 architecture
+   -------------------------------------------------------------------------- */
+	
+#if i386_TARGET_ARCH	
+
+.text
+        .align 2
+
+#ifdef LEADING_UNDERSCORE	
+.globl _StgRun
+_StgRun:
+#else	
+.globl StgRun
+StgRun:
+#endif
+	pushl %ebp		/* standard frame-pointer stuff */
+        movl %esp,%ebp
+
+	/*
+	 * leave a giant chunk of C-stack for temporaries in the STG world.
+	 */
+	subl $RESERVED_C_STACK_BYTES + 4*SIZEOF_LONG,%esp
+
+	/* 
+	 * save callee-saves registers on behalf of the STG code.
+	 */
+	leal RESERVED_C_STACK_BYTES(%esp),%eax
+        movl %ebx,0(%eax)
+        movl %esi,4(%eax)
+        movl %edi,8(%eax)
+        movl %ebp,12(%eax)
+
+	/*
+	 * grab the function argument from the stack, and jump to it.
+	 */
+        movl 8(%ebp),%eax
+        jmp *%eax
+
+        .align 2
+
+#ifdef LEADING_UNDERSCORE
+.globl _StgReturn
+_StgReturn:
+#else	
+.globl StgReturn
+StgReturn:
+#endif	
+	movl %esi,%eax   /* Return value in R1  */
+
+	/*
+	 * restore callee-saves registers.  (Don't stomp on %eax!)
+	 */
+	leal RESERVED_C_STACK_BYTES(%esp),%edx
+        movl 0(%edx),%ebx	/* restore the registers saved above */
+        movl 4(%edx),%esi
+        movl 8(%edx),%edi
+        movl 12(%edx),%ebp
+
+	movl %ebp, %esp		/* restore the C stack state */
+	popl %ebp
+        ret
+
+#endif /* i386_TARGET_ARCH */
+
+/* -----------------------------------------------------------------------------
+   Alpha architecture
+   -------------------------------------------------------------------------- */
+	
+/* -----------------------------------------------------------------------------
+   hppa1.1-hp-hpux architecture
+   -------------------------------------------------------------------------- */
+	
+/* -----------------------------------------------------------------------------
+   MIPS architecture
+   -------------------------------------------------------------------------- */
+	
+#endif /* !USE_MINIINTERPRETER */