 | | Re: anyone know how to check free space on RCX?
|
|
Albert Huang, Sorry for the confusion. "most significant" = upper 16 bits and "least significant" = lower 16 bits (the free memory is a 32 bit value). If you write the values out, you will get the 32 bit value (both values are hex) ... for example: (...) (22 years ago, 11-Jul-02, to lugnet.robotics.rcx.legos)
|
| |
| | Re: anyone know how to check free space on RCX?
|
|
While the declaration for mm_free_mem is int mm_free_mem(void) The fact is that the RCX has only 32K of memory available. 32K in hex is 0x8000... there's never a need for more than 4 digits in hex. Looking at key_handler() in kernel/program.c (the (...) (22 years ago, 11-Jul-02, to lugnet.robotics.rcx.legos)
|
| |
| | Re: anyone know how to check free space on RCX?
|
|
That is very interesting Jason. It is interesting that mm_free_mem() returns a 16bit value using a 32bit return code. Both int and long are 32bit value on most computers/compilers these days; short would be a 16bit value; and char would be an 8bit (...) (22 years ago, 11-Jul-02, to lugnet.robotics.rcx.legos)
|
| |
| | Re: anyone know how to check free space on RCX?
|
|
(...) int is defined as the natural width of the processor, which on a 16-bit processor is 16 bits. longs are 64 bits on some machines as well, so you can't assume it is always 32 bits -- if your code cares, use sizeof. (...) 32-bit math on the H8 (...) (22 years ago, 12-Jul-02, to lugnet.robotics.rcx.legos)
|
| |
| | Re: anyone know how to check free space on RCX?
|
|
(...) According to config/h8300/h8300.h in the gcc sources, int is 32bit for the h8 cross compiler. I believe the reason mm_free_mem() returns an int is because the memory manager stores the size of each free block as size_t, which is defined in (...) (22 years ago, 12-Jul-02, to lugnet.robotics.rcx.legos)
|
| |
| | Re: anyone know how to check free space on RCX?
|
|
(...) My sources (gcc-3.0) say: #define INT_TYPE_SIZE (TARGET_INT32 ? 32 : 16) A short experiment revealed that sizeof(short)=sizeof(int)=2, sizeof(long)=4. So int is normally 16bit. Only with the switch "-mint32" I get 32 bit ints. This is with a (...) (22 years ago, 12-Jul-02, to lugnet.robotics.rcx.legos)
|
| |
| | Re: anyone know how to check free space on RCX?
|
|
(...) This can't be right. I'm about 99% sure that all of the ints I've used with my legOS programs have been 2 bytes. When using LNP to send RCX ints to a PC, for example, you have to use short on the PC end of things to make it all work right. (...) (22 years ago, 12-Jul-02, to lugnet.robotics.rcx.legos)
|
| |
| | Re: anyone know how to check free space on RCX?
|
|
(...) The header is ok, but int is 2 bytes = 16 bit. You can check this with this highly optimized program: #include <conio.h> int main(int argc, char *argv[]) { lcd_int( sizeof( int ) ); for(;;) ; return 0; } And in the kernel sources, mm.c says (...) (22 years ago, 12-Jul-02, to lugnet.robotics.rcx.legos)
|
| |
| | Re: anyone know how to check free space on RCX?
|
|
John A. Tamplin, Jason Clark, Jochen Hoenicke and Michael J Ash: Thank you all for addressing these issues! It all make sense after reading the preceeding messages. I appologize for causing confusion. I am glad, however, to get it straight. ??So (...) (22 years ago, 12-Jul-02, to lugnet.robotics.rcx.legos)
|
| |
| | Re: anyone know how to check free space on RCX?
|
|
(...) Thanks for conducting the test... being 200+ miles away from my RCX this was bugging me :). My sources (gcc-2.95.2) have the same #define... but with the following about 120 lines earlier: /* Make int's 32 bits. */ #define TARGET_INT32 (...) (22 years ago, 12-Jul-02, to lugnet.robotics.rcx.legos)
|
