diff options
| author | Daniel Hellstrom <daniel@gaisler.com> | 2014-06-05 11:43:02 +0200 |
|---|---|---|
| committer | Daniel Cederman <cederman@gaisler.com> | 2014-06-27 11:03:25 +0200 |
| commit | 7d9b72e7d33187d134150286713fb5f01bf13cbd (patch) | |
| tree | ef65dfea4b548639bfc1d366a088d9104646d1b2 | |
| parent | 747c25d7179c41677d74841795fc6135a8764871 (diff) | |
SPARC: support for runtime FPU detection
With this patch it is possible to compile a kernel that works on
both FPU and non-FPU SPARC systems. The SPARC PSR register contains
a bit indicating if FPU is present.
It is a minimal increase to the foot-print.
| -rw-r--r-- | cpukit/score/cpu/sparc/cpu_asm.S | 17 | ||||
| -rw-r--r-- | cpukit/score/cpu/sparc/rtems/score/sparc.h | 10 |
2 files changed, 24 insertions, 3 deletions
diff --git a/cpukit/score/cpu/sparc/cpu_asm.S b/cpukit/score/cpu/sparc/cpu_asm.S index 92674de783..15f9dd26e1 100644 --- a/cpukit/score/cpu/sparc/cpu_asm.S +++ b/cpukit/score/cpu/sparc/cpu_asm.S @@ -55,7 +55,13 @@ SYM(_CPU_Context_save_fp): or %l1, %lo(SPARC_PSR_EF_MASK), %l1 or %l0, %l1, %l0 mov %l0, %psr ! **** ENABLE FLOAT ACCESS **** - nop; nop; nop; ! Need three nops before EF is + nop; nop; nop; ! Need three nops before EF is +#ifdef SPARC_DYNAMIC_FPU_DETECTION + mov %psr, %l0 ! **** check whether fpu present **** + andcc %l0,%l1,%g0 + beq 1f + nop +#endif ld [%i0], %l0 ! active due to pipeline delay!!! std %f0, [%l0 + FO_F1_OFFSET] std %f2, [%l0 + F2_F3_OFFSET] @@ -104,7 +110,13 @@ SYM(_CPU_Context_restore_fp): or %l1, %lo(SPARC_PSR_EF_MASK), %l1 or %l0, %l1, %l0 mov %l0, %psr ! **** ENABLE FLOAT ACCESS **** - nop; nop; nop; ! Need three nops before EF is + nop; nop; nop; ! Need three nops before EF is +#ifdef SPARC_DYNAMIC_FPU_DETECTION + mov %psr, %l0 ! **** check whether fpu present **** + andcc %l0,%l1,%g0 + beq 1f + nop +#endif ld [%i0], %l0 ! active due to pipeline delay!!! ldd [%l0 + FO_F1_OFFSET], %f0 ldd [%l0 + F2_F3_OFFSET], %f2 @@ -123,6 +135,7 @@ SYM(_CPU_Context_restore_fp): ldd [%l0 + F28_F29_OFFSET], %f28 ldd [%l0 + F3O_F31_OFFSET], %f30 ld [%l0 + FSR_OFFSET], %fsr +1: ret restore diff --git a/cpukit/score/cpu/sparc/rtems/score/sparc.h b/cpukit/score/cpu/sparc/rtems/score/sparc.h index abd0f8b987..e3251d8473 100644 --- a/cpukit/score/cpu/sparc/rtems/score/sparc.h +++ b/cpukit/score/cpu/sparc/rtems/score/sparc.h @@ -63,11 +63,19 @@ extern "C" { #define SPARC_NUMBER_OF_REGISTER_WINDOWS 8 /** + * Compile the SPARC kernel with runtime FPU detection. This is used + * by RTEMS kernels built without FPU but still need to be able to + * run tasks with FPU enabled. This way the kernel is SPARC (v7/v8) + * with or without FPU compatible. + */ +#define SPARC_DYNAMIC_FPU_DETECTION 1 + +/** * This macro indicates whether this multilib variation has hardware * floating point or not. We use the gcc cpp predefine _SOFT_FLOAT * to determine that. */ -#if defined(_SOFT_FLOAT) +#if !defined(SPARC_DYNAMIC_FPU_DETECTION) && defined(_SOFT_FLOAT) #define SPARC_HAS_FPU 0 #else #define SPARC_HAS_FPU 1 |