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///** @file
//
// Contains low level routines for the Virtual Machine implementation
// on an Itanium-based platform.
//
// Copyright (c) 2006 - 2008, Intel Corporation. <BR>
// All rights reserved. This program and the accompanying materials
// are licensed and made available under the terms and conditions of the BSD License
// which accompanies this distribution. The full text of the license may be found at
// http://opensource.org/licenses/bsd-license.php
//
// THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
// WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
//
//**/
.file "EbcLowLevel.s"
#define PROCEDURE_ENTRY(name) .##text; \
.##type name, @function; \
.##proc name; \
name::
#define PROCEDURE_EXIT(name) .##endp name
// Note: use of NESTED_SETUP requires number of locals (l) >= 3
#define NESTED_SETUP(i,l,o,r) \
alloc loc1=ar##.##pfs,i,l,o,r ;\
mov loc0=b0
#define NESTED_RETURN \
mov b0=loc0 ;\
mov ar##.##pfs=loc1 ;;\
br##.##ret##.##dpnt b0;;
.type CopyMem, @function;
//-----------------------------------------------------------------------------
//++
// EbcAsmLLCALLEX
//
// Implements the low level EBC CALLEX instruction. Sets up the
// stack pointer, does the spill of function arguments, and
// calls the native function. On return it restores the original
// stack pointer and returns to the caller.
//
// Arguments :
//
// On Entry :
// in0 = Address of native code to call
// in1 = New stack pointer
//
// Return Value:
//
// As per static calling conventions.
//
//--
//---------------------------------------------------------------------------
;// void EbcAsmLLCALLEX (UINTN FunctionAddr, UINTN EbcStackPointer)
PROCEDURE_ENTRY(EbcAsmLLCALLEX)
NESTED_SETUP (2,6,8,0)
// NESTED_SETUP uses loc0 and loc1 for context save
//
// Save a copy of the EBC VM stack pointer
//
mov r8 = in1;;
//
// Copy stack arguments from EBC stack into registers.
// Assume worst case and copy 8.
//
ld8 out0 = [r8], 8;;
ld8 out1 = [r8], 8;;
ld8 out2 = [r8], 8;;
ld8 out3 = [r8], 8;;
ld8 out4 = [r8], 8;;
ld8 out5 = [r8], 8;;
ld8 out6 = [r8], 8;;
ld8 out7 = [r8], 8;;
//
// Save the original stack pointer
//
mov loc2 = r12;
//
// Save the gp
//
or loc3 = r1, r0
//
// Set the new aligned stack pointer. Reserve space for the required
// 16-bytes of scratch area as well.
//
add r12 = 48, in1
//
// Now call the function. Load up the function address from the descriptor
// pointed to by in0. Then get the gp from the descriptor at the following
// address in the descriptor.
//
ld8 r31 = [in0], 8;;
ld8 r30 = [in0];;
mov b1 = r31
mov r1 = r30
(p0) br.call.dptk.many b0 = b1;;
//
// Restore the original stack pointer and gp
//
mov r12 = loc2
or r1 = loc3, r0
//
// Now return
//
NESTED_RETURN
PROCEDURE_EXIT(EbcAsmLLCALLEX)
//-----------------------------------------------------------------------------
//++
// EbcLLCALLEXNative
//
// This function is called to execute an EBC CALLEX instruction.
// This instruction requires that we thunk out to external native
// code. On return, we restore the stack pointer to its original location.
// Destroys no working registers. For IPF, at least 8 register slots
// must be allocated on the stack frame to support any number of
// arguments beiung passed to the external native function. The
// size of the stack frame is FramePtr - EbcSp. If this size is less
// than 64-bytes, the amount of stack frame allocated is rounded up
// to 64-bytes
//
// Arguments On Entry :
// in0 = CallAddr The function address.
// in1 = EbcSp The new EBC stack pointer.
// in2 = FramePtr The frame pointer.
//
// Return Value:
// None
//
// C Function Prototype:
// VOID
// EFIAPI
// EbcLLCALLEXNative (
// IN UINTN CallAddr,
// IN UINTN EbcSp,
// IN VOID *FramePtr
// );
//--
//---------------------------------------------------------------------------
PROCEDURE_ENTRY(EbcLLCALLEXNative)
NESTED_SETUP (3,6,3,0)
mov loc2 = in2;; // loc2 = in2 = FramePtr
mov loc3 = in1;; // loc3 = in1 = EbcSp
sub loc2 = loc2, loc3;; // loc2 = loc2 - loc3 = FramePtr - EbcSp
mov out2 = loc2;; // out2 = loc2 = FramePtr - EbcSp
mov loc4 = 0x40;; // loc4 = 0x40
cmp.leu p6 = out2, loc4;; // IF out2 < loc4 THEN P6=1 ELSE P6=0; IF (FramePtr - EbcSp) < 0x40 THEN P6 = 1 ELSE P6=0
(p6) mov loc2 = loc4;; // IF P6==1 THEN loc2 = loc4 = 0x40
mov loc4 = r12;; // save sp
or loc5 = r1, r0 // save gp
sub r12 = r12, loc2;; // sp = sp - loc2 = sp - MAX (0x40, FramePtr - EbcSp)
and r12 = -0x10, r12 // Round sp down to the nearest 16-byte boundary
mov out1 = in1;; // out1 = EbcSp
mov out0 = r12;; // out0 = sp
adds r12 = -0x8, r12
(p0) br.call.dptk.many b0 = CopyMem;; // CopyMem (sp, EbcSp, (FramePtr - EbcSp))
adds r12 = 0x8, r12
mov out0 = in0;; // out0 = CallAddr
mov out1 = r12;; // out1 = sp
(p0) br.call.dptk.many b0 = EbcAsmLLCALLEX;; // EbcAsmLLCALLEX (CallAddr, sp)
mov r12 = loc4;; // restore sp
or r1 = loc5, r0 // restore gp
NESTED_RETURN
PROCEDURE_EXIT(EbcLLCALLEXNative)
//
// UINTN EbcLLGetEbcEntryPoint(VOID)
//
// Description:
// Simply return, so that the caller retrieves the return register
// contents (R8). That's where the thunk-to-ebc code stuffed the
// EBC entry point.
//
PROCEDURE_ENTRY(EbcLLGetEbcEntryPoint)
br.ret.sptk b0 ;;
PROCEDURE_EXIT(EbcLLGetEbcEntryPoint)
//
// INT64 EbcLLGetReturnValue(VOID)
//
// Description:
// This function is called to get the value returned by native code
// to EBC. It simply returns because the return value should still
// be in the register, so the caller just gets the unmodified value.
//
PROCEDURE_ENTRY(EbcLLGetReturnValue)
br.ret.sptk b0 ;;
PROCEDURE_EXIT(EbcLLGetReturnValue)
//
// UINTN EbcLLGetStackPointer(VOID)
//
PROCEDURE_ENTRY(EbcLLGetStackPointer)
mov r8 = r12 ;;
br.ret.sptk b0 ;;
br.sptk.few b6
PROCEDURE_EXIT(EbcLLGetStackPointer)
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