diff --git a/src/isa-thumb.c b/src/isa-thumb.c
index 9fc1e1d0f..9be964d50 100644
--- a/src/isa-thumb.c
+++ b/src/isa-thumb.c
@@ -122,12 +122,18 @@ DEFINE_DATA_FORM_1_INSTRUCTION_THUMB(SUB, ARM_STUB)
 #define DEFINE_DATA_FORM_2_INSTRUCTION_EX_THUMB(NAME, IMMEDIATE, BODY) \
 	DEFINE_INSTRUCTION_THUMB(NAME, \
 		int immediate = IMMEDIATE; \
+		int rd = opcode & 0x0007; \
+		int rn = (opcode >> 3) & 0x0007; \
 		BODY;)
 
 #define DEFINE_DATA_FORM_2_INSTRUCTION_THUMB(NAME, BODY) \
 	COUNT_3(DEFINE_DATA_FORM_2_INSTRUCTION_EX_THUMB, NAME ## 1_, BODY)
 
-DEFINE_DATA_FORM_2_INSTRUCTION_THUMB(ADD, ARM_STUB)
+DEFINE_DATA_FORM_2_INSTRUCTION_THUMB(ADD, \
+	int n = cpu->gprs[rn]; \
+	cpu->gprs[rd] = n + immediate; \
+	THUMB_ADDITION_S(n, immediate, cpu->gprs[rd]))
+
 DEFINE_DATA_FORM_2_INSTRUCTION_THUMB(SUB, ARM_STUB)
 
 #define DEFINE_DATA_FORM_3_INSTRUCTION_EX_THUMB(NAME, RD, BODY) \