BSB: Provisional parser and generator of packets

diff --git a/test-bsb/gen.c b/test-bsb/gen.c
new file mode 100644 (file)
index 0000000..fb4fdbf
--- /dev/null
+++ b/test-bsb/gen.c
@@ -0,0 +1,41 @@
+#include <stdio.h>
+#include <stdint.h>
+
+typedef unsigned char byte;
+typedef unsigned int uint;
+typedef uint16_t u16;
+
+u16 crc_update(u16 crc, byte data)
+{
+       crc = crc ^ (data << 8);
+       for (uint i=0; i<8; i++) {
+               if (crc & 0x8000)
+                       crc = (crc << 1) ^ 0x1021;
+               else
+                       crc <<= 1;
+       }
+       return crc;
+}
+
+byte msg[] = {
+       0xdc,                   // sync
+       0x80 | 0x42,            // src
+       0x00,                   // dest
+       0x00,                   // length (will be filled)
+       0x06,                   // command
+       0x3d, 0x2e, 0x11, 0x25,
+};
+
+int main(void)
+{
+       msg[3] = sizeof(msg) + 2;
+
+       u16 crc = 0;
+       for (uint i=0; i < sizeof(msg); i++) {
+               printf("%02x ", msg[i]);
+               crc = crc_update(crc, msg[i]);
+       }
+       printf("%02x %02x\n", crc >> 8, crc & 0xff);
+
+       return 0;
+}

diff --git a/test-bsb/parse.c b/test-bsb/parse.c
new file mode 100644 (file)
index 0000000..bec15a1
--- /dev/null
+++ b/test-bsb/parse.c
@@ -0,0 +1,86 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+
+typedef unsigned char byte;
+typedef unsigned int uint;
+typedef uint16_t u16;
+
+uint rd(void)
+{
+       uint x;
+       if (scanf("%x", &x) == 1)
+               return x;
+       else {
+               puts("EOF");
+               exit(1);
+       }
+}
+
+u16 crc_update(u16 crc, byte data)
+{
+       crc = crc ^ (data << 8);
+       for (uint i=0; i<8; i++) {
+               if (crc & 0x8000)
+                       crc = (crc << 1) ^ 0x1021;
+               else
+                       crc <<= 1;
+       }
+       return crc;
+}
+
+int main(void)
+{
+       byte pkt[256];
+
+       for (;;) {
+               pkt[0] = rd();
+               if (pkt[0] != 0xdc) {
+                       printf("# Bad sync: %02x\n", pkt[0]);
+                       continue;
+               }
+
+               int len = 1;
+               while (len < 4 || len < pkt[3]) {
+                       pkt[len++] = rd();
+               }
+
+               for (int i=0; i<len; i++)
+                       printf("%02x ", pkt[i]);
+
+               u16 crc = 0;
+               for (int i=0; i<len; i++)
+                       crc = crc_update(crc, pkt[i]);
+               if (crc) {
+                       printf("[BAD CRC]\n");
+                       continue;
+               }
+               len -= 2;
+
+               if (len < 9) {
+                       printf("[TOO SHORT]\n");
+                       continue;
+               }
+
+               printf("\n\t%02x -> %02x: ", pkt[1], pkt[2]);
+               switch (pkt[4]) {
+                       case 2:
+                               printf("INFO %04x:%04x =", (pkt[5]<<8) | pkt[6], (pkt[7]<<8) | pkt[8]);
+                               for (int i=9; i<len; i++)
+                                       printf(" %02x", pkt[i]);
+                               putchar('\n');
+                               break;
+                       case 6:
+                               printf("GET %04x:%04x\n", (pkt[6]<<8) | pkt[5], (pkt[7]<<8) | pkt[8]);
+                               break;
+                       case 7:
+                               printf("RET %04x:%04x =", (pkt[5]<<8) | pkt[6], (pkt[7]<<8) | pkt[8]);
+                               for (int i=9; i<len; i++)
+                                       printf(" %02x", pkt[i]);
+                               putchar('\n');
+                               break;
+                       default:
+                               printf("??? type=%02x\n", pkt[4]);
+               }
+       }
+}