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https://github.com/rdolbeau/NuBusFPGA.git
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213 lines
7.3 KiB
C
213 lines
7.3 KiB
C
#ifndef __NUBUSFPGA_CSR_COMMON_H__
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#define __NUBUSFPGA_CSR_COMMON_H__
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/* from hw/common.h, +a32 */
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/* CSR data width (subreg. width) in bytes, for direct comparson to sizeof() */
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#define CSR_DW_BYTES (CONFIG_CSR_DATA_WIDTH/8)
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#define CSR_OFFSET_BYTES 4
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/* Number of subregs required for various total byte sizes, by subreg width:
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* NOTE: 1, 2, 4, and 8 bytes represent uint[8|16|32|64]_t C types; However,
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* CSRs of intermediate byte sizes (24, 40, 48, and 56) are NOT padded
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* (with extra unallocated subregisters) to the next valid C type!
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* +-----+-----------------+
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* | csr | bytes |
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* | _dw | 1 2 3 4 5 6 7 8 |
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* | |-----=---=-=-=---|
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* | 1 | 1 2 3 4 5 6 7 8 |
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* | 2 | 1 1 2 2 3 3 4 4 |
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* | 4 | 1 1 1 1 2 2 2 2 |
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* | 8 | 1 1 1 1 1 1 1 1 |
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* +-----+-----------------+ */
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__attribute__ ((section (".text.primary"))) static inline int num_subregs(int csr_bytes)
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{
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return (csr_bytes - 1) / CSR_DW_BYTES + 1;
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}
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/* Read a CSR of size 'csr_bytes' located at address 'a'. */
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__attribute__ ((section (".text.primary"))) static inline uint64_t _csr_rd(uint32_t a32, unsigned long a, int csr_bytes)
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{
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uint64_t r = __builtin_bswap32(*((uint32_t*)(a32 + a)));
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for (int i = 1; i < num_subregs(csr_bytes); i++) {
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r <<= CONFIG_CSR_DATA_WIDTH;
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a += CSR_OFFSET_BYTES;
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r |= __builtin_bswap32(*((uint32_t*)(a32 + a)));
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}
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return r;
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}
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/* Write value 'v' to a CSR of size 'csr_bytes' located at address 'a'. */
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__attribute__ ((section (".text.primary"))) static inline void _csr_wr(uint32_t a32, unsigned long a, uint64_t v, int csr_bytes)
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{
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int ns = num_subregs(csr_bytes);
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for (int i = 0; i < ns; i++) {
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*((uint32_t*)(a32 + a)) = __builtin_bswap32(v >> (CONFIG_CSR_DATA_WIDTH * (ns - 1 - i)));
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a += CSR_OFFSET_BYTES;
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}
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}
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// FIXME: - should we provide 24, 40, 48, and 56 bit csr_[rd|wr] methods?
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__attribute__ ((section (".text.primary"))) static inline uint8_t csr_rd_uint8(uint32_t a32, unsigned long a)
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{
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return _csr_rd(a32, a, sizeof(uint8_t));
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}
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__attribute__ ((section (".text.primary"))) static inline void csr_wr_uint8(uint32_t a32, uint8_t v, unsigned long a)
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{
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_csr_wr(a32, a, v, sizeof(uint8_t));
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}
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__attribute__ ((section (".text.primary"))) static inline uint16_t csr_rd_uint16(uint32_t a32, unsigned long a)
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{
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return _csr_rd(a32, a, sizeof(uint16_t));
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}
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__attribute__ ((section (".text.primary"))) static inline void csr_wr_uint16(uint32_t a32, uint16_t v, unsigned long a)
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{
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_csr_wr(a32, a, v, sizeof(uint16_t));
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}
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__attribute__ ((section (".text.primary"))) static inline uint32_t csr_rd_uint32(uint32_t a32, unsigned long a)
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{
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return _csr_rd(a32, a, sizeof(uint32_t));
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}
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__attribute__ ((section (".text.primary"))) static inline void csr_wr_uint32(uint32_t a32, uint32_t v, unsigned long a)
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{
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_csr_wr(a32, a, v, sizeof(uint32_t));
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}
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__attribute__ ((section (".text.primary"))) static inline uint64_t csr_rd_uint64(uint32_t a32, unsigned long a)
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{
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return _csr_rd(a32, a, sizeof(uint64_t));
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}
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__attribute__ ((section (".text.primary"))) static inline void csr_wr_uint64(uint32_t a32, uint64_t v, unsigned long a)
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{
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_csr_wr(a32, a, v, sizeof(uint64_t));
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}
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/* Read a CSR located at address 'a' into an array 'buf' of 'cnt' elements.
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*
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* NOTE: Since CSR_DW_BYTES is a constant here, we might be tempted to further
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* optimize things by leaving out one or the other of the if() branches below,
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* depending on each unsigned type width;
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* However, this code is also meant to serve as a reference for how CSRs are
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* to be manipulated by other programs (e.g., an OS kernel), which may benefit
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* from dynamically handling multiple possible CSR subregister data widths
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* (e.g., by passing a value in through the Device Tree).
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* Ultimately, if CSR_DW_BYTES is indeed a constant, the compiler should be
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* able to determine on its own whether it can automatically optimize away one
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* of the if() branches! */
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#define _csr_rd_buf(a32, a, buf, cnt) \
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{ \
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int i, j, nsubs, n_sub_elem; \
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uint64_t r; \
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if (sizeof(buf[0]) >= CSR_DW_BYTES) { \
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/* one or more subregisters per element */ \
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for (i = 0; i < cnt; i++) { \
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buf[i] = _csr_rd(a32, a, sizeof(buf[0])); \
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a += CSR_OFFSET_BYTES * num_subregs(sizeof(buf[0])); \
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} \
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} else { \
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/* multiple elements per subregister (2, 4, or 8) */ \
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nsubs = num_subregs(sizeof(buf[0]) * cnt); \
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n_sub_elem = CSR_DW_BYTES / sizeof(buf[0]); \
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for (i = 0; i < nsubs; i++) { \
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r = __builtin_bswap32(*(uint32_t*)(a32 + a)); \
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for (j = n_sub_elem - 1; j >= 0; j--) { \
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if (i * n_sub_elem + j < cnt) \
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buf[i * n_sub_elem + j] = r; \
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r >>= sizeof(buf[0]) * 8; \
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} \
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a += CSR_OFFSET_BYTES; \
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} \
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} \
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}
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/* Write an array 'buf' of 'cnt' elements to a CSR located at address 'a'.
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*
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* NOTE: The same optimization considerations apply here as with _csr_rd_buf()
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* above.
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*/
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#define _csr_wr_buf(a32, a, buf, cnt) \
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{ \
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int i, j, nsubs, n_sub_elem; \
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uint64_t v; \
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if (sizeof(buf[0]) >= CSR_DW_BYTES) { \
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/* one or more subregisters per element */ \
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for (i = 0; i < cnt; i++) { \
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_csr_wr(a32, a, buf[i], sizeof(buf[0])); \
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a += CSR_OFFSET_BYTES * num_subregs(sizeof(buf[0])); \
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} \
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} else { \
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/* multiple elements per subregister (2, 4, or 8) */ \
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nsubs = num_subregs(sizeof(buf[0]) * cnt); \
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n_sub_elem = CSR_DW_BYTES / sizeof(buf[0]); \
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for (i = 0; i < nsubs; i++) { \
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v = buf[i * n_sub_elem + 0]; \
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for (j = 1; j < n_sub_elem; j++) { \
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if (i * n_sub_elem + j == cnt) \
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break; \
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v <<= sizeof(buf[0]) * 8; \
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v |= buf[i * n_sub_elem + j]; \
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} \
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*((uint32_t*)(a32 + a)) = __builtin_bswap32(v); \
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a += CSR_OFFSET_BYTES; \
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} \
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} \
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}
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__attribute__ ((section (".text.primary"))) static inline void csr_rd_buf_uint8(uint32_t a32, unsigned long a, uint8_t *buf, int cnt)
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{
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_csr_rd_buf(a32, a, buf, cnt);
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}
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__attribute__ ((section (".text.primary"))) static inline void csr_wr_buf_uint8(uint32_t a32, unsigned long a,
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const uint8_t *buf, int cnt)
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{
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_csr_wr_buf(a32, a, buf, cnt);
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}
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__attribute__ ((section (".text.primary"))) static inline void csr_rd_buf_uint16(uint32_t a32, unsigned long a, uint16_t *buf, int cnt)
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{
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_csr_rd_buf(a32, a, buf, cnt);
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}
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__attribute__ ((section (".text.primary"))) static inline void csr_wr_buf_uint16(uint32_t a32, unsigned long a,
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const uint16_t *buf, int cnt)
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{
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_csr_wr_buf(a32, a, buf, cnt);
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}
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__attribute__ ((section (".text.primary"))) static inline void csr_rd_buf_uint32(uint32_t a32, unsigned long a, uint32_t *buf, int cnt)
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{
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_csr_rd_buf(a32, a, buf, cnt);
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}
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__attribute__ ((section (".text.primary"))) static inline void csr_wr_buf_uint32(uint32_t a32, unsigned long a,
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const uint32_t *buf, int cnt)
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{
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_csr_wr_buf(a32, a, buf, cnt);
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}
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/* NOTE: the macros' "else" branch is unreachable, no need to be warned
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* about a >= 64bit left shift! */
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#pragma GCC diagnostic push
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#pragma GCC diagnostic ignored "-Wshift-count-overflow"
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__attribute__ ((section (".text.primary"))) static inline void csr_rd_buf_uint64(uint32_t a32, unsigned long a, uint64_t *buf, int cnt)
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{
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_csr_rd_buf(a32, a, buf, cnt);
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}
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__attribute__ ((section (".text.primary"))) static inline void csr_wr_buf_uint64(uint32_t a32, unsigned long a,
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const uint64_t *buf, int cnt)
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{
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_csr_wr_buf(a32, a, buf, cnt);
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}
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#pragma GCC diagnostic pop
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#endif // __NUBUSFPGA_CSR_COMMON_H__
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