esp-idf/components/riscv/instruction_decode.c

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/*
* SPDX-FileCopyrightText: 2020-2024 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#include <stdlib.h>
#include "riscv/instruction_decode.h"
typedef union {
struct {
unsigned int opcode: 7;
unsigned int rd: 5;
int imm_19_12: 8;
int imm_11: 1;
int imm_10_1: 10;
int imm20: 1;
};
unsigned int inst;
} riscv_jal_intruction_t;
int riscv_decode_offset_from_jal_instruction(const intptr_t inst_addr)
{
riscv_jal_intruction_t *jal_inst = (riscv_jal_intruction_t *)inst_addr;
// check if it's a valid JAL instruction
if (jal_inst->opcode != 0x6f && jal_inst->rd != 0) {
abort();
}
return (jal_inst->imm_10_1 | jal_inst->imm_11 << 10 | jal_inst->imm_19_12 << 11 | jal_inst->imm20 << 19) << 1;
}