diff options
| -rw-r--r-- | src/server/gdb_server.c | 104 |
1 files changed, 73 insertions, 31 deletions
diff --git a/src/server/gdb_server.c b/src/server/gdb_server.c index ea92d3b..8798ae0 100644 --- a/src/server/gdb_server.c +++ b/src/server/gdb_server.c @@ -149,30 +149,11 @@ int check_pending(struct connection *connection, int timeout_s, int *got_data) return ERROR_OK; } -int gdb_get_char(struct connection *connection, int* next_char) +static int gdb_get_char_inner(struct connection *connection, int* next_char) { struct gdb_connection *gdb_con = connection->priv; int retval = ERROR_OK; -#ifdef _DEBUG_GDB_IO_ - char *debug_buffer; -#endif - - if (gdb_con->buf_cnt-- > 0) - { - *next_char = *(gdb_con->buf_p++); - if (gdb_con->buf_cnt > 0) - connection->input_pending = 1; - else - connection->input_pending = 0; - -#ifdef _DEBUG_GDB_IO_ - LOG_DEBUG("returned char '%c' (0x%2.2x)", *next_char, *next_char); -#endif - - return ERROR_OK; - } - for (;;) { if (connection->service->type == CONNECTION_PIPE) @@ -257,6 +238,50 @@ int gdb_get_char(struct connection *connection, int* next_char) return retval; } +/** + * The cool thing about this fn is that it allows buf_p and buf_cnt to be + * held in registers in the inner loop. + * + * For small caches and embedded systems this is important! + */ +static inline int gdb_get_char_fast(struct connection *connection, int* next_char, char **buf_p, int *buf_cnt) +{ + int retval = ERROR_OK; + + if ((*buf_cnt)-- > 0) + { + *next_char = **buf_p; + (*buf_p)++; + if (*buf_cnt > 0) + connection->input_pending = 1; + else + connection->input_pending = 0; + +#ifdef _DEBUG_GDB_IO_ + LOG_DEBUG("returned char '%c' (0x%2.2x)", *next_char, *next_char); +#endif + + return ERROR_OK; + } + + struct gdb_connection *gdb_con = connection->priv; + gdb_con->buf_p = *buf_p; + gdb_con->buf_cnt = *buf_cnt; + retval = gdb_get_char_inner(connection, next_char); + *buf_p = gdb_con->buf_p; + *buf_cnt = gdb_con->buf_cnt; + + return retval; +} + + +int gdb_get_char(struct connection *connection, int* next_char) +{ + struct gdb_connection *gdb_con = connection->priv; + return gdb_get_char_fast(connection, next_char, &gdb_con->buf_p, &gdb_con->buf_cnt); +} + + int gdb_putback_char(struct connection *connection, int last_char) { struct gdb_connection *gdb_con = connection->priv; @@ -461,27 +486,33 @@ static __inline__ int fetch_packet(struct connection *connection, int *checksum_ unsigned char my_checksum = 0; char checksum[3]; int character; - int retval; + int retval = ERROR_OK; struct gdb_connection *gdb_con = connection->priv; my_checksum = 0; int count = 0; count = 0; + + /* move this over into local variables to use registers and give the + * more freedom to optimize */ + char *buf_p = gdb_con->buf_p; + int buf_cnt = gdb_con->buf_cnt; + for (;;) { /* The common case is that we have an entire packet with no escape chars. * We need to leave at least 2 bytes in the buffer to have * gdb_get_char() update various bits and bobs correctly. */ - if ((gdb_con->buf_cnt > 2) && ((gdb_con->buf_cnt + count) < *len)) + if ((buf_cnt > 2) && ((buf_cnt + count) < *len)) { /* The compiler will struggle a bit with constant propagation and * aliasing, so we help it by showing that these values do not * change inside the loop */ int i; - char *buf = gdb_con->buf_p; - int run = gdb_con->buf_cnt - 2; + char *buf = buf_p; + int run = buf_cnt - 2; i = 0; int done = 0; while (i < run) @@ -513,19 +544,21 @@ static __inline__ int fetch_packet(struct connection *connection, int *checksum_ buffer[count++] = character & 0xff; } } - gdb_con->buf_p += i; - gdb_con->buf_cnt -= i; + buf_p += i; + buf_cnt -= i; if (done) break; } if (count > *len) { LOG_ERROR("packet buffer too small"); - return ERROR_GDB_BUFFER_TOO_SMALL; + retval = ERROR_GDB_BUFFER_TOO_SMALL; + break; } - if ((retval = gdb_get_char(connection, &character)) != ERROR_OK) - return retval; + retval = gdb_get_char_fast(connection, &character, &buf_p, &buf_cnt); + if (retval != ERROR_OK) + break; if (character == '#') break; @@ -535,8 +568,11 @@ static __inline__ int fetch_packet(struct connection *connection, int *checksum_ /* data transmitted in binary mode (X packet) * uses 0x7d as escape character */ my_checksum += character & 0xff; - if ((retval = gdb_get_char(connection, &character)) != ERROR_OK) - return retval; + + retval = gdb_get_char_fast(connection, &character, &buf_p, &buf_cnt); + if (retval != ERROR_OK) + break; + my_checksum += character & 0xff; buffer[count++] = (character ^ 0x20) & 0xff; } @@ -547,6 +583,12 @@ static __inline__ int fetch_packet(struct connection *connection, int *checksum_ } } + gdb_con->buf_p = buf_p; + gdb_con->buf_cnt = buf_cnt; + + if (retval != ERROR_OK) + return retval; + *len = count; if ((retval = gdb_get_char(connection, &character)) != ERROR_OK) |