cpu_ebi.h

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/*
 * Copyright (C) 2021 Gerson Fernando Budke
 *
 * This file is subject to the terms and conditions of the GNU Lesser
 * General Public License v2.1. See the file LICENSE in the top level
 * directory for more details.
 */
 
#include "periph_cpu.h"
 
#ifndef CPU_EBI_H
#define CPU_EBI_H
 
#ifdef __cplusplus
extern "C" {
#endif
 
typedef uint32_t hugemem_ptr_t;
 
#define HUGEMEM_NULL        0
 
void ebi_init(void);
 
static inline uint8_t hugemem_read8(const hugemem_ptr_t from)
{
    uint8_t value;
 
    __asm__ volatile (
        /* place 24 bit address into r30, r31, RAMPZ
         * r31:r30     <- %B[from]:%A[from]
         * RAMPZ       <- %C[from]
         */
        "movw   r30,        %A[from]           \n\t"
        "out    %[rampz],   %C[from]           \n\t"
        /* read byte from 24 bit address
         * register    <- *(RAMPZ + Z)
         */
        "ld     %[dest],    Z                  \n\t"
        /* clear ramp */
        "out    %[rampz],   __zero_reg__       \n\t"
        : [dest]    "=r"(value)
        : [from]    "r"(from),
          [rampz]   "i"(&RAMPZ)
        : "r30", "r31"
    );
 
    return value;
}
 
static inline void hugemem_write8(hugemem_ptr_t to, uint8_t val)
{
    __asm__ volatile (
        /* place 24 bit address into r30, r31, RAMPZ
         * r31:r30     <- %B[from]:%A[from]
         * RAMPZ       <- %C[from]
         */
        "movw   r30,        %A[to]             \n\t"
        "out    %[rampz],   %C[to]             \n\t"
        /* write byte to 24 bit address
         * (RAMPZ + Z) <- register
         */
        "st     Z,          %[val]             \n\t"
        /* clear ramp */
        "out    %[rampz],   __zero_reg__       \n\t"
        :
        : [to]      "r"(to),
          [val]     "r"(val),
          [rampz]   "i"(&RAMPZ)
        : "r30", "r31"
    );
}
 
uint16_t hugemem_read16(const hugemem_ptr_t from);
 
void hugemem_write16(hugemem_ptr_t to, uint16_t val);
 
uint32_t hugemem_read32(const hugemem_ptr_t from);
 
void hugemem_write32(hugemem_ptr_t to, uint32_t val);
 
void hugemem_read_block(void *to, const hugemem_ptr_t from, size_t size);
 
void hugemem_write_block(hugemem_ptr_t to, const void *from, size_t size);
 
#ifdef __cplusplus
}
#endif
 
#endif /* CPU_EBI_H */