Changed register pair handling in M68K header

* instead of using bit operations, we now leverage the size of the
  enclosing union to avoid running code and provide a more convenient
  interface to the library user.

arch/M68K/M68KDisassembler.c

@@ -979,19 +979,21 @@ static void build_cas2(m68k_info *info, int size)
 
 	op0->address_mode = M68K_AM_NONE;
 	op0->type = M68K_OP_REG_PAIR;
-	op0->register_bits = (((extension >> 16) & 7) << 4) | (extension & 7);
+	op0->reg_pair.reg_0 = (extension >> 16) & 7;
+	op0->reg_pair.reg_1 = extension & 7;
 
 	op1->address_mode = M68K_AM_NONE;
 	op1->type = M68K_OP_REG_PAIR;
-	op1->register_bits = (((extension >> 22) & 7) << 4) | ((extension >> 6) & 7);
+	op1->reg_pair.reg_0 = (extension >> 22) & 7;
+	op1->reg_pair.reg_1 = (extension >> 6) & 7;
 
 	reg_0 = (extension >> 28) & 7;
 	reg_1 = (extension >> 12) & 7;
 
 	op2->address_mode = M68K_AM_NONE;
 	op2->type = M68K_OP_REG_PAIR;
-	op2->register_bits = ((reg_0 + (BIT_1F(extension) ? 8 : 0)) << 4) |
-		(reg_1 + (BIT_F(extension) ? 8 : 0));
+	op2->reg_pair.reg_0 = reg_0 + (BIT_1F(extension) ? 8 : 0);
+	op2->reg_pair.reg_1 = reg_1 + (BIT_F(extension) ? 8 : 0);
 }
 
 static void build_chk2_cmp2(m68k_info *info, int size)
@@ -2244,7 +2246,8 @@ static void d68020_divl(m68k_info *info)
 
 	op1->address_mode = M68K_AM_NONE;
 	op1->type = M68K_OP_REG_PAIR;
-	op1->register_bits = (reg_0 << 4) | reg_1;
+	op1->reg_pair.reg_0 = reg_0;
+	op1->reg_pair.reg_1 = reg_1;
 
 	if ((reg_0 == reg_1) || !BIT_A(extension)) {
 		op1->type = M68K_OP_REG;
@@ -2789,7 +2792,8 @@ static void d68020_mull(m68k_info *info)
 
 	op1->address_mode = M68K_AM_NONE;
 	op1->type = M68K_OP_REG_PAIR;
-	op1->register_bits = (reg_0 << 4) | reg_1;
+	op1->reg_pair.reg_0 = reg_0;
+	op1->reg_pair.reg_1 = reg_1;
 
 	if (!BIT_A(extension)) {
 		op1->type = M68K_OP_REG;

include/capstone/m68k.h

@@ -112,7 +112,8 @@ typedef enum m68k_op_type {
 	M68K_OP_REG,         // = CS_OP_REG (Register operand).
 	M68K_OP_IMM,         // = CS_OP_IMM (Immediate operand).
 	M68K_OP_MEM,         // = CS_OP_MEM (Memory operand).
-	M68K_OP_FP,          // = CS_OP_FP  (Floating-Point operand)
+	M68K_OP_FP_SINGLE,   // single precision Floating-Point operand
+	M68K_OP_FP_DOUBLE,   // double precision Floating-Point operand
 	M68K_OP_REG_BITS,    // Register bits move
 	M68K_OP_REG_PAIR,    // Register pair in the same op (upper 4 bits for first reg, lower for second) 
 } m68k_op_type;
@@ -136,12 +137,16 @@ typedef struct m68k_op_mem {
 // Instruction operand
 typedef struct cs_m68k_op {
 	union {
-		uint64_t imm;           // immediate value for IMM operand
+		uint64_t imm;               // immediate value for IMM operand
 		double dimm; 		    // double imm
 		float simm; 		    // float imm
 		m68k_reg reg;		    // register value for REG operand
+		struct {		    // register pair in one operand
+			m68k_reg reg_0;
+			m68k_reg reg_1;
+		} reg_pair;
 		m68k_op_mem mem; 	    // data when operand is targeting memory
-		uint32_t register_bits; // register bits for movem/cas2/etc (always in d0-d7, a0-a7, fp0 - fp7 order)
+		uint32_t register_bits; // register bits for movem etc. (always in d0-d7, a0-a7, fp0 - fp7 order)
 	};
 	m68k_op_type type;
 	m68k_address_mode address_mode;	// M68K addressing mode for this op