Improve code and clarify parameters to ABI_Push/PopRegistersAndAdjustStack.

- Factor common work into a helper function.
- Replace confusingly named "noProlog" with "rsp_alignment".  Now that
x86 is not supported, we can just specify it explicitly as 8 for
clarity.
- Add the option to include more frame size, which I'll need later.
- Revert a change by magumagu in March which replaced MOVAPD with MOVUPD
on account of 32-bit Windows, since it's no longer supported.  True,
apparently recent processors don't execute the former any faster if the
pointer is, in fact, aligned, but there's no point using MOVUPD for
something that's guaranteed to be aligned...

(I discovered that GenFrsqrte and GenFres were incorrectly passing false
to noProlog - they were, in fact, functions without prologs, the
original meaning of the parameter - which caused the previous change to
break.  This is now fixed.)

Source/Core/Common/x64ABI.cpp

@@ -36,67 +36,86 @@ void XEmitter::ABI_RestoreStack(unsigned int frameSize, bool noProlog)
 	}
 }
 
-void XEmitter::ABI_PushRegistersAndAdjustStack(u32 mask, bool noProlog)
+void XEmitter::ABI_CalculateFrameSize(u32 mask, size_t rsp_alignment, size_t needed_frame_size, size_t* shadowp, size_t* subtractionp, size_t* xmm_offsetp)
 {
-	int regSize = 8;
-	int shadow = 0;
+	size_t shadow = 0;
 #if defined(_WIN32)
 	shadow = 0x20;
 #endif
+
 	int count = 0;
 	for (int r = 0; r < 16; r++)
 	{
 		if (mask & (1 << r))
-		{
-			PUSH((X64Reg) r);
 			count++;
-		}
 	}
-	int size = ((noProlog ? -regSize : 0) - (count * regSize)) & 0xf;
+	rsp_alignment -= count * 8;
+	size_t subtraction = 0;
+	if (mask & 0xffff0000)
+	{
+		// If we have any XMMs to save, we must align the stack here.
+		subtraction = rsp_alignment & 0xf;
+	}
 	for (int x = 0; x < 16; x++)
 	{
 		if (mask & (1 << (16 + x)))
-			size += 16;
-	}
-	size += shadow;
-	if (size)
-		SUB(regSize * 8, R(RSP), size >= 0x80 ? Imm32(size) : Imm8(size));
-	int offset = shadow;
-	for (int x = 0; x < 16; x++)
-	{
-		if (mask & (1 << (16 + x)))
-		{
-			MOVUPD(MDisp(RSP, offset), (X64Reg) x);
-			offset += 16;
-		}
+			subtraction += 16;
 	}
+	size_t xmm_base_subtraction = subtraction;
+	subtraction += needed_frame_size;
+	subtraction += shadow;
+	// Final alignment.
+	rsp_alignment -= subtraction;
+	subtraction += rsp_alignment & 0xf;
+
+	*shadowp = shadow;
+	*subtractionp = subtraction;
+	*xmm_offsetp = subtraction - xmm_base_subtraction;
 }
 
-void XEmitter::ABI_PopRegistersAndAdjustStack(u32 mask, bool noProlog)
+size_t XEmitter::ABI_PushRegistersAndAdjustStack(u32 mask, size_t rsp_alignment, size_t needed_frame_size)
 {
-	int regSize = 8;
-	int size = 0;
-#if defined(_WIN32)
-	size += 0x20;
-#endif
+	size_t shadow, subtraction, xmm_offset;
+	ABI_CalculateFrameSize(mask, rsp_alignment, needed_frame_size, &shadow, &subtraction, &xmm_offset);
+
+	for (int r = 0; r < 16; r++)
+	{
+		if (mask & (1 << r))
+			PUSH((X64Reg) r);
+	}
+
+	if (subtraction)
+		SUB(64, R(RSP), subtraction >= 0x80 ? Imm32((u32)subtraction) : Imm8((u8)subtraction));
+
 	for (int x = 0; x < 16; x++)
 	{
 		if (mask & (1 << (16 + x)))
 		{
-			MOVUPD((X64Reg) x, MDisp(RSP, size));
-			size += 16;
+			MOVAPD(MDisp(RSP, (int)xmm_offset), (X64Reg) x);
+			xmm_offset += 16;
 		}
 	}
-	int count = 0;
-	for (int r = 0; r < 16; r++)
-	{
-		if (mask & (1 << r))
-			count++;
-	}
-	size += ((noProlog ? -regSize : 0) - (count * regSize)) & 0xf;
 
-	if (size)
-		ADD(regSize * 8, R(RSP), size >= 0x80 ? Imm32(size) : Imm8(size));
+	return shadow;
+}
+
+void XEmitter::ABI_PopRegistersAndAdjustStack(u32 mask, size_t rsp_alignment, size_t needed_frame_size)
+{
+	size_t shadow, subtraction, xmm_offset;
+	ABI_CalculateFrameSize(mask, rsp_alignment, needed_frame_size, &shadow, &subtraction, &xmm_offset);
+
+	for (int x = 0; x < 16; x++)
+	{
+		if (mask & (1 << (16 + x)))
+		{
+			MOVAPD((X64Reg) x, MDisp(RSP, (int)xmm_offset));
+			xmm_offset += 16;
+		}
+	}
+
+	if (subtraction)
+		ADD(64, R(RSP), subtraction >= 0x80 ? Imm32((u32)subtraction) : Imm8((u8)subtraction));
+
 	for (int r = 15; r >= 0; r--)
 	{
 		if (mask & (1 << r))

Source/Core/Common/x64ABI.h

@@ -53,5 +53,7 @@
 
 #endif // WIN32
 
+#define ABI_ALL_CALLEE_SAVED ((u32) ~ABI_ALL_CALLER_SAVED)
+
 #define ABI_RETURN RAX
 

Source/Core/Common/x64Emitter.h

@@ -281,6 +281,8 @@ private:
 	void WriteFloatLoadStore(int bits, FloatOp op, FloatOp op_80b, OpArg arg);
 	void WriteNormalOp(XEmitter *emit, int bits, NormalOp op, const OpArg &a1, const OpArg &a2);
 
+	void ABI_CalculateFrameSize(u32 mask, size_t rsp_alignment, size_t needed_frame_size, size_t* shadowp, size_t* subtractionp, size_t* xmm_offsetp);
+
 protected:
 	inline void Write8(u8 value)   {*code++ = value;}
 	inline void Write16(u16 value) {*(u16*)code = (value); code += 2;}
@@ -761,9 +763,11 @@ public:
 	void ABI_PushAllCalleeSavedRegsAndAdjustStack();
 	void ABI_PopAllCalleeSavedRegsAndAdjustStack();
 
-	// A more flexible version of the above.
-	void ABI_PushRegistersAndAdjustStack(u32 mask, bool noProlog);
-	void ABI_PopRegistersAndAdjustStack(u32 mask, bool noProlog);
+	// Saves/restores the registers and adjusts the stack to be aligned as
+	// required by the ABI, where the previous alignment was as specified.
+	// Push returns the size of the shadow space, i.e. the offset of the frame.
+	size_t ABI_PushRegistersAndAdjustStack(u32 mask, size_t rsp_alignment, size_t needed_frame_size = 0);
+	void ABI_PopRegistersAndAdjustStack(u32 mask, size_t rsp_alignment, size_t needed_frame_size = 0);
 
 	unsigned int ABI_GetAlignedFrameSize(unsigned int frameSize, bool noProlog = false);
 	void ABI_AlignStack(unsigned int frameSize, bool noProlog = false);