[PATCH v4 2/5] RISC-V: add helpers for J-type immediate handling

[Heiko Stuebner]

From: Heiko Stuebner <heiko.stuebner at vrull.eu>

Similar to the helper for the u-type + i-type imm handling, add helper-
functions for j-type immediates.

While it also would be possible to open-code that bit of imm wiggling
using the macros already provided in insn.h, it's way better to have
consistency on how we handle this across all function encoding/decoding.

Signed-off-by: Heiko Stuebner <heiko.stuebner at vrull.eu>
---
 arch/riscv/include/asm/insn.h | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/arch/riscv/include/asm/insn.h b/arch/riscv/include/asm/insn.h
index 0455b4dcb0a7..9eea61a3028f 100644
--- a/arch/riscv/include/asm/insn.h
+++ b/arch/riscv/include/asm/insn.h
@@ -301,6 +301,32 @@ static __always_inline bool riscv_insn_is_branch(u32 code)
 	(RVC_X(x_, RVC_B_IMM_7_6_OPOFF, RVC_B_IMM_7_6_MASK) << RVC_B_IMM_7_6_OFF) | \
 	(RVC_IMM_SIGN(x_) << RVC_B_IMM_SIGN_OFF); })
 
+/*
+ * Get the immediate from a J-type instruction.
+ *
+ * @insn: instruction to process
+ * Return: immediate
+ */
+static inline s32 riscv_insn_extract_jtype_imm(u32 insn)
+{
+	return RV_EXTRACT_JTYPE_IMM(insn);
+}
+
+/*
+ * Update a J-type instruction with an immediate value.
+ *
+ * @insn: pointer to the jtype instruction
+ * @imm: the immediate to insert into the instruction
+ */
+static inline void riscv_insn_insert_jtype_imm(u32 *insn, s32 imm)
+{
+	*insn &= ~GENMASK(31, 12);
+	*insn |= (((imm & (RV_J_IMM_10_1_MASK << RV_J_IMM_10_1_OFF)) << RV_I_IMM_11_0_OPOFF) |
+		  ((imm & (RV_J_IMM_11_MASK << RV_J_IMM_11_OFF)) << RV_J_IMM_11_OPOFF) |
+		  ((imm & (RV_J_IMM_19_12_OPOFF << RV_J_IMM_19_12_OFF)) << RV_J_IMM_19_12_OPOFF) |
+		  ((imm & (1 << RV_J_IMM_SIGN_OFF)) << RV_J_IMM_SIGN_OPOFF));
+}
+
 /*
  * Put together one immediate from a U-type and I-type instruction pair.
  *
-- 
2.35.1