From 37e91de03d499527cab001b3f55ac9a63438993d Mon Sep 17 00:00:00 2001
From: Michael <20937441+KMikeeU@users.noreply.github.com>
Date: Tue, 14 Apr 2026 00:04:38 +0200
Subject: [PATCH] add custom instruction

---
 src/tinyriscv.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/tinyriscv.h b/src/tinyriscv.h
index 8d1c1e9..b25ed85 100644
--- a/src/tinyriscv.h
+++ b/src/tinyriscv.h
@@ -89,6 +89,17 @@ inline void tinyriscv_I_type(const u8 funct3, const u8 funct7, u32* x,
 
 ////////////////////////////////////////////////////////////////////////////////
 
+__attribute__((always_inline)) 
+inline void tinyriscv_custom_I_type(const u8 funct3, const u8 funct7, u32* x,
+	const u8 rd, const u8 rs1, const i16 imm, const u8 shamt){
+
+	switch (funct3) {
+	case /*CUSTOM XOR*/ 0: x[rd] = ((x[rs1] << (i32)imm) ^ 0xFF) >> (i32)imm; break;
+	}
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
 __attribute__((always_inline)) 
 inline void tinyriscv_R_type(const u8 funct3, const u8 funct7, u32* x, 
 	const u8 rd, const u8 rs1, const u8 rs2){
@@ -199,6 +210,9 @@ void tinyriscv_step(tinyriscv_core* core){
 	case /*I-type*/ 0x13: 
 		tinyriscv_I_type(funct3, funct7, core->x, rd, rs1, imm_i, rs2); 
 		break;
+	case /*Custom-I-type*/ 0x0B:
+		tinyriscv_custom_I_type(funct3, funct7, core->x, rd, rs1, imm_i, rs2);
+		break;
 	case /*R-type*/ 0x33: 
 		tinyriscv_R_type(funct3, funct7, core->x, rd, rs1, rs2); 
 		break;