Imagelibrary/rtems
1
0
Fork 1
mirror of https://gitlab.rtems.org/rtems/rtos/rtems.git synced 2025-12-26 22:48:23 +00:00
Code Issues Packages Projects Releases Wiki Activity

Added I386_HAS_BSWAP cpu model feature flag so swap u32 could take

Browse Source 
advantage of this instruction.

Also up conditionals mapping cpu models to feature flags by having a
section which defaults all the i386 family feature flags to the most
common value.
This commit is contained in:
Joel Sherrill
1998-04-27 18:18:13 +00:00
parent b0aba4c46b
commit 0c508af979
1 changed files with 28 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

38
c/src/exec/score/cpu/i386/i386.h
View File

@@ -36,25 +36,30 @@ extern "C" {
* i486sx
* pentium
*
* Floating point is the only feature which currently varies. Eventually
* the i486-plus level instruction for endian swapping should be added
* to this feature list.
* CPU Model Feature Flags:
*
* I386_HAS_BSWAP: Defined to "1" if the instruction for endian swapping
* (bswap) should be used. This instruction appears to
* be present in all i486's and above.
*
* I386_HAS_FPU: Defined to "1" if the CPU has an FPU.
*
*/
#if defined(i386_fp)
#define CPU_MODEL_NAME "i386 with i387"
#define I386_HAS_FPU 1
#define I386_HAS_BSWAP 0
#elif defined(i386_nofp)
#define CPU_MODEL_NAME "i386 w/o i387"
#define I386_HAS_FPU 0
#define I386_HAS_FPU 0
#define I386_HAS_BSWAP 0
#elif defined(i486dx)
#define CPU_MODEL_NAME "i486dx"
#define I386_HAS_FPU 1
#elif defined(i486sx)
@@ -64,7 +69,6 @@ extern "C" {
#elif defined(pentium)
#define CPU_MODEL_NAME "Pentium"
#define I386_HAS_FPU 1
#else
@@ -72,6 +76,20 @@ extern "C" {
#endif
/*
* Set default values for CPU model feature flags
*
* NOTE: These settings are chosen to reflect most of the family members.
*/
#ifndef I386_HAS_FPU
#define I386_HAS_FPU 1
#endif
#ifndef I386_HAS_BSWAP
#define I386_HAS_BSWAP 1
#endif
/*
* Define the name of the CPU family.
*/
@@ -167,13 +185,13 @@ static inline unsigned int i386_swap_U32(
{
unsigned long lout;
#if (I386_HAS_BSWAP == 0)
asm volatile( "rorw $8,%%ax;"
"rorl $16,%0;"
"rorw $8,%%ax" : "=a" (lout) : "0" (value) );
/* this should be better for i486dx and above */
/*
#else
__asm__ volatile( "bswap %0" : "=r" (lout) : "0" (lin));
*/
#endif
return( lout );
}