diff options
author | Eric S. Raymond <esr@thyrsus.com> | 2005-06-10 21:23:02 +0000 |
---|---|---|
committer | Eric S. Raymond <esr@thyrsus.com> | 2005-06-10 21:23:02 +0000 |
commit | 5e9ad018406fbfdd3a21e191f3c1aafa8ec2c108 (patch) | |
tree | 47ded8f037b7e8164c05da92161c89a2daf7d08a /bits.h | |
parent | af369699cfdf433cc8114565603a24fa2d09e3ea (diff) | |
download | gpsd-5e9ad018406fbfdd3a21e191f3c1aafa8ec2c108.tar.gz |
New version of bits.h with fixed-width types for cross-architecture portability.
Also, the bit-getter macros from zodiac.c now live here.
Diffstat (limited to 'bits.h')
-rw-r--r-- | bits.h | 46 |
1 files changed, 25 insertions, 21 deletions
@@ -1,21 +1,17 @@ /* * bits.h - extract binary data from message buffer - * * These macros extract bytes, words, longwords, floats or doubles from + * + * These macros extract bytes, words, longwords, floats or doubles from * a message that contains these items in MSB-first byte order. * By defining the GET_ORIGIN and PUT_ORIGIN macros, it's possible to * change the origin of the indexing. * - * assumptions: + * Assumptions: * char is 8 bits, short is 16 bits, int is 32 bits, long long is 64 bits, * float is 32 bits IEEE754, double is 64 bits IEEE754. * - * it would be possible to use types like int16_t from header files to enforce - * these assumptions, but splint does not understand those and will scream. - * also, using such explicitly sized types usually causes warnings at many - * other places in a program (like when calling library routines). we will - * need to consider this again when we want to port to an architecture which - * implements differently sized types. Noth 32- and 64-bit systems with - * gcc are OK. + * The use of fixed-length types in the casts enforces these. + * Both 32- and 64-bit systems with gcc are OK with this set. */ union int_float { @@ -31,22 +27,30 @@ union long_double { #ifndef GET_ORIGIN #define GET_ORIGIN 0 #endif - -#define getsb(buf, off) ((char)buf[GET_ORIGIN+(off)]) -#define getub(buf, off) (buf[GET_ORIGIN+(off)]) -#define getsw(buf, off) ((short)(((unsigned)getub(buf, off) << 8) | (unsigned)getub(buf, off+1))) -#define getuw(buf, off) ((unsigned short)(((unsigned)getub(buf, off) << 8) | (unsigned)getub(buf, off+1))) -#define getsl(buf, off) ((int)(((unsigned)getuw(buf, off) << 16) | getuw(buf, off+2))) -#define getul(buf, off) ((unsigned int)(((unsigned)getuw(buf, off) << 16) | getuw(buf, off+2))) -#define getsL(buf, off) ((long long)(((unsigned long long)getul(buf, off) << 32) | getul(buf, off+4))) -#define getuL(buf, off) ((unsigned long long)(((unsigned long long)getul(buf, off) << 32) | getul(buf, off+4))) -#define getf(buf, off) (i_f.i = getsl(buf, off), i_f.f) -#define getd(buf, off) (l_d.l = getsL(buf, off), l_d.d) - #ifndef PUT_ORIGIN #define PUT_ORIGIN 0 #endif +/* SiRF and most other GPS protocols use big-endian (network byte order) */ +#define getsb(buf, off) ((int8_t)buf[GET_ORIGIN+(off)]) +#define getub(buf, off) ((u_int8_t)buf[GET_ORIGIN+(off)]) +#define getsw(buf, off) ((int16_t)(((u_int16_t)getub(buf, off) << 8) | (u_int16_t)getub(buf, off+1))) +#define getuw(buf, off) ((u_int16_t)(((u_int16_t)getub(buf, off) << 8) | (u_int16_t)getub(buf, off+1))) +#define getsl(buf, off) ((int32_t)(((u_int16_t)getuw(buf, off) << 16) | getuw(buf, off+2))) +#define getul(buf, off) ((u_int32_t)(((u_int16_t)getuw(buf, off) << 16) | getuw(buf, off+2))) +#define getsL(buf, off) ((int64_t)(((u_int64_t)getul(buf, off) << 32) | getul(buf, off+4))) +#define getuL(buf, off) ((u_int64_t)(((u_int64_t)getul(buf, off) << 32) | getul(buf, off+4))) +#define getf(buf, off) (i_f.i = getsl(buf, off), i_f.f) +#define getd(buf, off) (l_d.l = getsL(buf, off), l_d.d) + #define putbyte(buf,off,b) {buf[PUT_ORIGIN+(off)] = (unsigned char)(b);} #define putword(buf,off,w) {putbyte(buf,off,(w) >> 8); putbyte(buf,off+1,w);} #define putlong(buf,off,l) {putword(buf,off,(l) >> 16); putword(buf,off+2,l);} + +/* Zodiac protocol description uses 1-origin indexing by little-endian word */ +#define getword(n) ( (session->outbuffer[2*(n)-2]) \ + | (session->outbuffer[2*(n)-1] << 8)) +#define getlong(n) ( (session->outbuffer[2*(n)-2]) \ + | (session->outbuffer[2*(n)-1] << 8) \ + | (session->outbuffer[2*(n)+0] << 16) \ + | (session->outbuffer[2*(n)+1] << 24)) |