From 7c9f368d6307da66d428a940ee193a5b4eb08e9b Mon Sep 17 00:00:00 2001
From: "Unknown W. Brackets" <checkins@unknownbrackets.org>
Date: Sat, 14 May 2016 14:21:53 -0700
Subject: [PATCH] jit-ir: Add some descriptions of mnemonics.

Sometimes I forget what vhdp etc. meant, let's make the VFPU code a bit
more accessible.
---
 Core/MIPS/IR/IRCompVFPU.cpp | 51 +++++++++++++++++++++++++++++++++++--
 1 file changed, 49 insertions(+), 2 deletions(-)

diff --git a/Core/MIPS/IR/IRCompVFPU.cpp b/Core/MIPS/IR/IRCompVFPU.cpp
index 1b484fbb60..a469a9cf81 100644
--- a/Core/MIPS/IR/IRCompVFPU.cpp
+++ b/Core/MIPS/IR/IRCompVFPU.cpp
@@ -315,6 +315,9 @@ namespace MIPSComp {
 			DISABLE;
 		}
 
+		// Vector init
+		// d[N] = CONST[N]
+
 		VectorSize sz = GetVecSize(op);
 		int type = (op >> 16) & 0xF;
 		int vd = _VD;
@@ -338,6 +341,9 @@ namespace MIPSComp {
 			DISABLE;
 		}
 
+		// Vector identity row
+		// d[N] = IDENTITY[N,m]
+
 		int vd = _VD;
 		VectorSize sz = GetVecSize(op);
 		u8 dregs[4];
@@ -374,6 +380,9 @@ namespace MIPSComp {
 			DISABLE;
 		}
 
+		// Matrix init
+		// d[N,M] = CONST[N,M]
+
 		// Not really about trying here, it will work if enabled.
 		VectorSize vsz = GetVectorSize(sz);
 		u8 vecs[4];
@@ -412,6 +421,10 @@ namespace MIPSComp {
 			DISABLE;
 		}
 
+		// Vector homogenous dot product
+		// d[0] = s[0 .. n-2] dot t[0 .. n-2] + t[n-1]
+		// Note: s[n-1] is ignored.
+
 		int vd = _VD;
 		int vs = _VS;
 		int vt = _VT;
@@ -448,6 +461,11 @@ namespace MIPSComp {
 		if (js.HasUnknownPrefix())
 			DISABLE;
 
+		// Vector horizontal add
+		// d[0] = s[0] + ... s[n-1]
+		// Vector horizontal average
+		// d[0] = (s[0] + ... s[n-1]) / n
+
 		VectorSize sz = GetVecSize(op);
 		int n = GetNumVectorElements(sz);
 
@@ -480,6 +498,9 @@ namespace MIPSComp {
 			DISABLE;
 		}
 
+		// Vector dot product
+		// d[0] = s[0 .. n-1] dot t[0 .. n-1]
+
 		int vd = _VD;
 		int vs = _VS;
 		int vt = _VT;
@@ -514,6 +535,9 @@ namespace MIPSComp {
 		if (js.HasUnknownPrefix())
 			DISABLE;
 
+		// Vector arithmetic
+		// d[N] = OP(s[N], t[N]) (see below)
+
 		// Check that we can support the ops, and prepare temporary values for ops that need it.
 		bool allowSIMD = true;
 		switch (op >> 26) {
@@ -672,6 +696,9 @@ namespace MIPSComp {
 		if (js.HasUnknownPrefix())
 			DISABLE;
 
+		// Vector unary operation
+		// d[N] = OP(s[N]) (see below)
+
 		int vs = _VS;
 		int vd = _VD;
 
@@ -787,6 +814,9 @@ namespace MIPSComp {
 			DISABLE;
 		}
 
+		// Vector integer to float
+		// d[N] = float(S[N]) * mult
+
 		VectorSize sz = GetVecSize(op);
 		int n = GetNumVectorElements(sz);
 
@@ -878,11 +908,12 @@ namespace MIPSComp {
 		EatPrefix();
 	}
 
-	// Good above
-
 	void IRFrontend::Comp_Vmfvc(MIPSOpcode op) {
 		CONDITIONAL_DISABLE;
 
+		// Vector Move from vector control reg
+		// S[0] = VFPU_CTRL[i]
+
 		int vs = _VS;
 		int imm = op & 0xFF;
 		if (imm >= 128 && imm < 128 + VFPU_CTRL_MAX) {
@@ -892,11 +923,17 @@ namespace MIPSComp {
 			// } else {
 			ir.Write(IROp::VfpuCtrlToReg, IRTEMP_0, imm - 128);
 			ir.Write(IROp::FMovFromGPR, vfpuBase + voffset[vs], IRTEMP_0);
+		} else {
+			DISABLE;
 		}
 	}
 
 	void IRFrontend::Comp_Vmtvc(MIPSOpcode op) {
 		CONDITIONAL_DISABLE;
+
+		// Vector Move from vector control reg
+		// VFPU_CTRL[i] = S[0]
+
 		int vs = _VS;
 		int imm = op & 0xFF;
 		if (imm >= 128 && imm < 128 + VFPU_CTRL_MAX) {
@@ -914,6 +951,9 @@ namespace MIPSComp {
 	void IRFrontend::Comp_Vmmov(MIPSOpcode op) {
 		CONDITIONAL_DISABLE;
 
+		// Matrix move
+		// D[N,M] = S[N,M]
+
 		int vs = _VS;
 		int vd = _VD;
 		// This probably ignores prefixes for all sane intents and purposes.
@@ -980,6 +1020,9 @@ namespace MIPSComp {
 			DISABLE;
 		}
 
+		// Vector scale, vector by scalar
+		// d[N] = s[N] * t[0]
+
 		VectorSize sz = GetVecSize(op);
 		int n = GetNumVectorElements(sz);
 
@@ -1134,6 +1177,10 @@ namespace MIPSComp {
 			DISABLE;
 		}
 
+		// Vertex transform, vector by matrix
+		// d[N] = s[N*m .. N*m + n-1] dot t[0 .. n-1]
+		// Homogenous means t[n-1] is treated as 1.
+
 		VectorSize sz = GetVecSize(op);
 		MatrixSize msz = GetMtxSize(op);
 		int n = GetNumVectorElements(sz);