diff --git a/include/sbi/riscv_encoding.h b/include/sbi/riscv_encoding.h
index e1256e31..f4df1ae4 100644
--- a/include/sbi/riscv_encoding.h
+++ b/include/sbi/riscv_encoding.h
@@ -1291,6 +1291,8 @@
 #define SHIFT_FUNCT3			12
 
 #define MASK_RS1			0xf8000
+#define MASK_RS2			0x1f00000
+#define MASK_RD				0xf80
 
 #define MASK_CSR			0xfff00000
 #define SHIFT_CSR			20
@@ -1356,28 +1358,17 @@
 #define SHIFT_RIGHT(x, y)		\
 	((y) < 0 ? ((x) << -(y)) : ((x) >> (y)))
 
-#define REG_MASK			\
-	((1 << (5 + LOG_REGBYTES)) - (1 << LOG_REGBYTES))
-
-#define REG_OFFSET(insn, pos)		\
-	(SHIFT_RIGHT((insn), (pos) - LOG_REGBYTES) & REG_MASK)
-
-#define REG_PTR(insn, pos, regs)	\
-	(ulong *)((ulong)(regs) + REG_OFFSET(insn, pos))
-
 #define GET_FUNC3(insn)			((insn & MASK_FUNCT3) >> SHIFT_FUNCT3)
 #define GET_RM(insn)			GET_FUNC3(insn)
-#define GET_RS1_NUM(insn)		((insn & MASK_RS1) >> 15)
+#define GET_RS1_NUM(insn)		((insn & MASK_RS1) >> SH_RS1)
+#define GET_RS2_NUM(insn)		((insn & MASK_RS2) >> SH_RS2)
+#define GET_RS1S_NUM(insn)		RVC_RS1S(insn)
+#define GET_RS2S_NUM(insn)		RVC_RS2S(insn)
+#define GET_RS2C_NUM(insn)		RVC_RS2(insn)
+#define GET_RD_NUM(insn)		((insn & MASK_RD) >> SH_RD)
 #define GET_CSR_NUM(insn)		((insn & MASK_CSR) >> SHIFT_CSR)
 #define GET_AQRL(insn)			((insn & MASK_AQRL) >> SHIFT_AQRL)
 
-#define GET_RS1(insn, regs)		(*REG_PTR(insn, SH_RS1, regs))
-#define GET_RS2(insn, regs)		(*REG_PTR(insn, SH_RS2, regs))
-#define GET_RS1S(insn, regs)		(*REG_PTR(RVC_RS1S(insn), 0, regs))
-#define GET_RS2S(insn, regs)		(*REG_PTR(RVC_RS2S(insn), 0, regs))
-#define GET_RS2C(insn, regs)		(*REG_PTR(insn, SH_RS2C, regs))
-#define GET_SP(regs)			(*REG_PTR(2, 0, regs))
-#define SET_RD(insn, regs, val)		(*REG_PTR(insn, SH_RD, regs) = (val))
 #define IMM_I(insn)			((s32)(insn) >> 20)
 #define IMM_S(insn)			(((s32)(insn) >> 25 << 5) | \
 					 (s32)(((insn) >> 7) & 0x1f))
diff --git a/include/sbi/sbi_trap.h b/include/sbi/sbi_trap.h
index 5eec4dab..731a0c98 100644
--- a/include/sbi/sbi_trap.h
+++ b/include/sbi/sbi_trap.h
@@ -127,70 +127,75 @@
 
 /** Representation of register state at time of trap/interrupt */
 struct sbi_trap_regs {
-	/** zero register state */
-	unsigned long zero;
-	/** ra register state */
-	unsigned long ra;
-	/** sp register state */
-	unsigned long sp;
-	/** gp register state */
-	unsigned long gp;
-	/** tp register state */
-	unsigned long tp;
-	/** t0 register state */
-	unsigned long t0;
-	/** t1 register state */
-	unsigned long t1;
-	/** t2 register state */
-	unsigned long t2;
-	/** s0 register state */
-	unsigned long s0;
-	/** s1 register state */
-	unsigned long s1;
-	/** a0 register state */
-	unsigned long a0;
-	/** a1 register state */
-	unsigned long a1;
-	/** a2 register state */
-	unsigned long a2;
-	/** a3 register state */
-	unsigned long a3;
-	/** a4 register state */
-	unsigned long a4;
-	/** a5 register state */
-	unsigned long a5;
-	/** a6 register state */
-	unsigned long a6;
-	/** a7 register state */
-	unsigned long a7;
-	/** s2 register state */
-	unsigned long s2;
-	/** s3 register state */
-	unsigned long s3;
-	/** s4 register state */
-	unsigned long s4;
-	/** s5 register state */
-	unsigned long s5;
-	/** s6 register state */
-	unsigned long s6;
-	/** s7 register state */
-	unsigned long s7;
-	/** s8 register state */
-	unsigned long s8;
-	/** s9 register state */
-	unsigned long s9;
-	/** s10 register state */
-	unsigned long s10;
-	/** s11 register state */
-	unsigned long s11;
-	/** t3 register state */
-	unsigned long t3;
-	/** t4 register state */
-	unsigned long t4;
-	/** t5 register state */
-	unsigned long t5;
-	/** t6 register state */
-	unsigned long t6;
+	union {
+		unsigned long gprs[32];
+		struct {
+			/** zero register state */
+			unsigned long zero;
+			/** ra register state */
+			unsigned long ra;
+			/** sp register state */
+			unsigned long sp;
+			/** gp register state */
+			unsigned long gp;
+			/** tp register state */
+			unsigned long tp;
+			/** t0 register state */
+			unsigned long t0;
+			/** t1 register state */
+			unsigned long t1;
+			/** t2 register state */
+			unsigned long t2;
+			/** s0 register state */
+			unsigned long s0;
+			/** s1 register state */
+			unsigned long s1;
+			/** a0 register state */
+			unsigned long a0;
+			/** a1 register state */
+			unsigned long a1;
+			/** a2 register state */
+			unsigned long a2;
+			/** a3 register state */
+			unsigned long a3;
+			/** a4 register state */
+			unsigned long a4;
+			/** a5 register state */
+			unsigned long a5;
+			/** a6 register state */
+			unsigned long a6;
+			/** a7 register state */
+			unsigned long a7;
+			/** s2 register state */
+			unsigned long s2;
+			/** s3 register state */
+			unsigned long s3;
+			/** s4 register state */
+			unsigned long s4;
+			/** s5 register state */
+			unsigned long s5;
+			/** s6 register state */
+			unsigned long s6;
+			/** s7 register state */
+			unsigned long s7;
+			/** s8 register state */
+			unsigned long s8;
+			/** s9 register state */
+			unsigned long s9;
+			/** s10 register state */
+			unsigned long s10;
+			/** s11 register state */
+			unsigned long s11;
+			/** t3 register state */
+			unsigned long t3;
+			/** t4 register state */
+			unsigned long t4;
+			/** t5 register state */
+			unsigned long t5;
+			/** t6 register state */
+			unsigned long t6;
+		};
+	};
 	/** mepc register state */
 	unsigned long mepc;
 	/** mstatus register state */
@@ -199,6 +204,21 @@ struct sbi_trap_regs {
 	unsigned long mstatusH;
 };
 
+_Static_assert(
+	sizeof(((struct sbi_trap_regs *)0)->gprs) ==
+	offsetof(struct sbi_trap_regs, t6) +
+	sizeof(((struct sbi_trap_regs *)0)->t6),
+	"struct sbi_trap_regs's layout differs between gprs and named members");
+
+#define REG_VAL(idx, regs)		((regs)->gprs[(idx)])
+
+#define GET_RS1(insn, regs)		REG_VAL(GET_RS1_NUM(insn), regs)
+#define GET_RS2(insn, regs)		REG_VAL(GET_RS2_NUM(insn), regs)
+#define GET_RS1S(insn, regs)		REG_VAL(GET_RS1S_NUM(insn), regs)
+#define GET_RS2S(insn, regs)		REG_VAL(GET_RS2S_NUM(insn), regs)
+#define GET_RS2C(insn, regs)		REG_VAL(GET_RS2C_NUM(insn), regs)
+#define SET_RD(insn, regs, val)		(REG_VAL(GET_RD_NUM(insn), regs) = (val))
+
 /** Representation of trap details */
 struct sbi_trap_info {
 	/** cause Trap exception cause */