diff --git a/include/PICA/shader.hpp b/include/PICA/shader.hpp
index 9fcf0a4b..c5af3443 100644
--- a/include/PICA/shader.hpp
+++ b/include/PICA/shader.hpp
@@ -12,7 +12,9 @@ enum class ShaderType {
 
 namespace ShaderOpcodes {
 	enum : u32 {
-		MOV = 0x13
+		DP4 = 0x02,
+		MOV = 0x13,
+		END = 0x22
 	};
 }
 
@@ -31,11 +33,13 @@ class PICAShader {
 	std::array<vec4f, 16> tempRegisters;
 	ShaderType type;
 
-	// Shader opcodes
-	void mov(u32 instruction);
 	vec4f getSource(u32 source);
 	vec4f& getDest(u32 dest);
 
+	// Shader opcodes
+	void dp4(u32 instruction);
+	void mov(u32 instruction);
+
 	// src1, src2 and src3 have different negation & component swizzle bits in the operand descriptor
 	// https://problemkaputt.github.io/gbatek.htm#3dsgpushaderinstructionsetopcodesummary in the
 	// "Shader Operand Descriptors" section
@@ -75,6 +79,14 @@ class PICAShader {
 		return ret;
 	}
 
+	template <int sourceIndex>
+	vec4f getSourceSwizzled(u32 source, u32 opDescriptor) {
+		vec4f srcVector = getSource(source);
+		srcVector = swizzle<sourceIndex>(srcVector, opDescriptor);
+
+		return srcVector;
+	}
+
 public:
 	std::array<u32, 512> loadedShader; // Currently loaded & active shader
 	std::array<u32, 512> bufferedShader; // Shader to be transferred when the SH_CODETRANSFER_END reg gets written to
diff --git a/src/core/PICA/shader_interpreter.cpp b/src/core/PICA/shader_interpreter.cpp
index f53eb6d2..b213b1ed 100644
--- a/src/core/PICA/shader_interpreter.cpp
+++ b/src/core/PICA/shader_interpreter.cpp
@@ -8,6 +8,8 @@ void PICAShader::run() {
 		const u32 opcode = instruction >> 26; // Top 6 bits are the opcode
 
 		switch (opcode) {
+			case ShaderOpcodes::DP4: dp4(instruction); break;
+			case ShaderOpcodes::END: return; // Stop running shader
 			case ShaderOpcodes::MOV: mov(instruction); break;
 			default:Helpers::panic("Unimplemented PICA instruction %08X (Opcode = %02X)", instruction, opcode);
 		}
@@ -15,16 +17,20 @@ void PICAShader::run() {
 }
 
 PICAShader::vec4f PICAShader::getSource(u32 source) {
-	if (source < 16)
+	if (source < 0x10)
 		return attributes[source];
-	else if (source >= 0x20 && source <= 0x7f)
+	else if (source < 0x20)
+		return tempRegisters[source - 0x10];
+	else if (source <= 0x7f)
 		return floatUniforms[source - 0x20];
 
 	Helpers::panic("[PICA] Unimplemented source value: %X", source);
 }
 
 PICAShader::vec4f& PICAShader::getDest(u32 dest) {
-	if (dest >= 0x10 && dest <= 0x1f) { // Temporary registers
+	if (dest <= 0x6) {
+		return outputs[dest];
+	} else if (dest >= 0x10 && dest <= 0x1f) { // Temporary registers
 		return tempRegisters[dest - 0x10];
 	}
 	Helpers::panic("[PICA] Unimplemented dest: %X", dest);
@@ -37,8 +43,7 @@ void PICAShader::mov(u32 instruction) {
 	const u32 dest = (instruction >> 21) & 0x1f;
 
 	if (idx) Helpers::panic("[PICA] MOV: idx != 0");
-	vec4f srcVector = getSource(src);
-	srcVector = swizzle<1>(srcVector, operandDescriptor);
+	vec4f srcVector = getSourceSwizzled<1>(src, operandDescriptor);
 	vec4f& destVector = getDest(dest);
 
 	// Destination component mask. Tells us which lanes of the destination register will be written to
@@ -48,4 +53,27 @@ void PICAShader::mov(u32 instruction) {
 			destVector[3 - i] = srcVector[3 - i];
 		}
 	}
+}
+
+void PICAShader::dp4(u32 instruction) {
+	const u32 operandDescriptor = operandDescriptors[instruction & 0x7f];
+	const u32 src1 = (instruction >> 12) & 0x7f;
+	const u32 src2 = (instruction >> 7) & 0x1f; // src2 coming first because PICA moment
+	const u32 idx = (instruction >> 19) & 3;
+	const u32 dest = (instruction >> 21) & 0x1f;
+
+	if (idx) Helpers::panic("[PICA] DP4: idx != 0");
+	vec4f srcVec1 = getSourceSwizzled<1>(src1, operandDescriptor);
+	vec4f srcVec2 = getSourceSwizzled<2>(src2, operandDescriptor);
+
+	vec4f& destVector = getDest(dest);
+	f24 dot = srcVec1[0] * srcVec2[0] + srcVec1[1] * srcVec2[1] + srcVec1[2] * srcVec2[2] + srcVec1[3] * srcVec2[3];
+
+	// Destination component mask. Tells us which lanes of the destination register will be written to
+	u32 componentMask = operandDescriptor & 0xf;
+	for (int i = 0; i < 4; i++) {
+		if (componentMask & (1 << i)) {
+			destVector[3 - i] = dot;
+		}
+	}
 }
\ No newline at end of file
diff --git a/src/core/PICA/shader_unit.cpp b/src/core/PICA/shader_unit.cpp
index 239fd75e..1e8377e9 100644
--- a/src/core/PICA/shader_unit.cpp
+++ b/src/core/PICA/shader_unit.cpp
@@ -18,7 +18,7 @@ void PICAShader::reset() {
 	opDescriptorIndex = 0;
 	f32UniformTransfer = false;
 
-	const vec4f zero = vec4f({ f24::fromFloat32(0.0), f24::fromFloat32(0.0), f24::fromFloat32(0.0), f24::fromFloat32(0.0) });
+	const vec4f zero = vec4f({ f24::zero(), f24::zero(), f24::zero(), f24::zero() });
 	attributes.fill(zero);
 	floatUniforms.fill(zero);
 	outputs.fill(zero);