In packing the structure, just beware of ALWAYS aligning a word variable to an even address, otherwise you'll end up in a mess. As a matter of fact, if you call a word instruction (like mov.w) with a word argument aligned at an odd address, the msp430 will zero out the most significant byte of the word.
R# 2009/7/24 Frank Harvey <[email protected]>: > I added arg -fpack-struct to the msp430-gcc command and the addresses started > incrementing by 1 as you would expect. > > msp430-gcc -S -fpack-struct main.c > > The problem smells like an old one I encountered on other machines where the > structs are actually the size you'd think - but, when something goes to > assign memory addresses to them, it pads the length to make it come out to > the next word boundary. This is generally "a speed thing" but it plays havoc > if you're trying to exactly map a set of structs over a just-arrived > communications message. > > frank > > > --- On Wed, 7/22/09, Stephen Douthit <[email protected]> wrote: > >> From: Stephen Douthit <[email protected]> >> Subject: Re: [Mspgcc-users] problem with iomacros.h >> To: "GCC for MSP430 - http://mspgcc.sf.net"; >> <[email protected]> >> Date: Wednesday, July 22, 2009, 7:58 PM >> On Wed, Jul 22, 2009 at 4:06 AM, >> Rainer Haape <[email protected]> >> wrote: >> >> > Hello, >> > I have a problem with iomacros.h under linux with the >> latest Versions of >> > mspgcc. >> > All ioregisters seem to be 16 Bit instead of 8 Bit, so >> all but one adresses >> > are wrong. >> > The following lines in c: >> > >> > #include <msp430x16x.h> >> > #include <iomacros.h> >> > >> > int main (void) >> > { >> > char i; >> > i = port1.in.pin1; >> // 0x0020 >> > port1.out.pin1 = 1; >> // 0x0021 >> > port1.dir.pin1 = 1; >> // 0x0022 >> > i = port1.ifg.pin1; >> // 0x0023 >> > port1.ie.pin1 = 1; >> // 0x0025 >> > port1.ies.pin1 = 1; >> // 0x0024 >> > port1.sel.pin1 = 1; >> // 0x0026 >> > } >> > >> > were compiled to: >> > --- snip --- >> > >> > int main (void) >> > { >> > 4036: 31 >> 40 00 39 mov >> #14592, r1 ;#0x3900 >> > char i; >> > i = port1.in.pin1; >> > 403a: e2 >> b3 20 00 >> bit.b #2, >> &0x0020 ;r3 As==10 >> > 403e: 4f >> 43 >> clr.b r15 >> > 4040: 4f >> 63 >> adc.b r15 >> > port1.out.pin1 = 1; >> > 4042: e2 >> d3 22 00 >> bis.b #2, >> &0x0022 ;r3 As==10 >> > port1.dir.pin1 = 1; >> > 4046: e2 >> d3 24 00 >> bis.b #2, >> &0x0024 ;r3 As==10 >> > i = port1.ifg.pin1; >> > 404a: e2 >> b3 26 00 >> bit.b #2, >> &0x0026 ;r3 As==10 >> > 404e: 4f >> 43 >> clr.b r15 >> > 4050: 4f >> 63 >> adc.b r15 >> > port1.ie.pin1 = 1; >> > 4052: e2 >> d3 2a 00 >> bis.b #2, >> &0x002a ;r3 As==10 >> > port1.ies.pin1 = 1; >> > 4056: e2 >> d3 28 00 >> bis.b #2, >> &0x0028 ;r3 As==10 >> > port1.sel.pin1 = 1; >> > 405a: e2 >> d3 2c 00 >> bis.b #2, >> &0x002c ;r3 As==10 >> > } >> > >> > --- snip --- >> > >> > What is going wrong? >> > >> > Thank you in advance, >> > Rainer Haape >> > [email protected] >> > >> > >> > >> > >> ------------------------------------------------------------------------------ >> > _______________________________________________ >> > Mspgcc-users mailing list >> > [email protected] >> > https://lists.sourceforge.net/lists/listinfo/mspgcc-users >> > >> >> >> I built the mspgcc toolchain on a Debian(Lenny) setup a few >> days ago, but >> hadn't tried it out until I saw your message. >> >> I got the same results you did, but after poking around the >> code a little I >> don't think there's anything wrong in iomacros.h. >> Instead, it looks like >> for some reason the ioregister_t union from >> msp430/iostructures.h is getting >> compled to twice the expected size. >> >> #include <msp430/iostructures.h> >> >> void main (void) >> { >> char i; >> i=sizeof(char); >> i=sizeof(ioregister_t); >> } >> >> compiles to: >> >> void main (void) >> { >> fc36: 31 40 7e >> 02 mov >> #638, r1 >> ;#0x027e >> fc3a: 04 >> 41 mov >> r1, r4 >> char i; >> i=sizeof(char); >> fc3c: d4 43 00 >> 00 mov.b #1, >> 0(r4) ;r3 As==01, >> 0x0000(r4) >> i=sizeof(ioregister_t); >> fc40: e4 43 00 >> 00 mov.b #2, >> 0(r4) ;r3 As==10, >> 0x0000(r4) >> } >> >> googling for mspgcc union errors gave me a bunch of reports >> of misaligned >> int reads from int/char unions, but nothing about the size >> of the union >> going haywire. >> >> Has anyone else seen/fixed this? >> >> Thanks, >> Steve >> >> -----Inline Attachment Follows----- >> >> ------------------------------------------------------------------------------ >> >> -----Inline Attachment Follows----- >> >> _______________________________________________ >> Mspgcc-users mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/mspgcc-users >> > > ------------------------------------------------------------------------------ > _______________________________________________ > Mspgcc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/mspgcc-users >
