diff --git a/InstructionSets/ARM/OperationMapper.hpp b/InstructionSets/ARM/OperationMapper.hpp
index 8552ea7de..aff28dd93 100644
--- a/InstructionSets/ARM/OperationMapper.hpp
+++ b/InstructionSets/ARM/OperationMapper.hpp
@@ -408,13 +408,9 @@ struct OperationMapper {
 		// page references are provided were more detailed versions of the
 		// decoding are depicted.
 
-		// Data processing; cf. p.17.
-		if constexpr (((partial >> 26) & 0b11) == 0b00) {
-			scheduler.template perform<i>(DataProcessing(instruction));
-			return;
-		}
-
 		// Multiply and multiply-accumulate (MUL, MLA); cf. p.23.
+		//
+		// This usurps a potential data processing decoding, so needs priority.
 		if constexpr (((partial >> 22) & 0b111'111) == 0b000'000) {
 			// This implementation provides only eight bits baked into the template parameters so
 			// an additional dynamic test is required to check whether this is really, really MUL or MLA.
@@ -424,6 +420,12 @@ struct OperationMapper {
 			}
 		}
 
+		// Data processing; cf. p.17.
+		if constexpr (((partial >> 26) & 0b11) == 0b00) {
+			scheduler.template perform<i>(DataProcessing(instruction));
+			return;
+		}
+
 		// Single data transfer (LDR, STR); cf. p.25.
 		if constexpr (((partial >> 26) & 0b11) == 0b01) {
 			scheduler.template perform<i>(SingleDataTransfer(instruction));
diff --git a/Machines/Acorn/Archimedes/Archimedes.cpp b/Machines/Acorn/Archimedes/Archimedes.cpp
index 574dd008e..6bd1a2027 100644
--- a/Machines/Acorn/Archimedes/Archimedes.cpp
+++ b/Machines/Acorn/Archimedes/Archimedes.cpp
@@ -702,7 +702,7 @@ class ConcreteMachine:
 
 					static bool log = false;
 					if(log) {
-						logger.info().append("%08x: %08x [r14:%08x]", executor_.pc(), instruction, executor_.registers()[14]);
+						logger.info().append("%08x: %08x [r0:%08x]", executor_.pc(), instruction, executor_.registers()[0]);
 					}
 					InstructionSet::ARM::execute<arm_model>(instruction, executor_);
 				}