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CPUs implementing MIPS32 R2 may include a 64-bit FPU, just as MIPS64 CPUs do. In order to preserve backwards compatibility a 64-bit FPU will act like a 32-bit FPU (by accessing doubles from the least significant 32 bits of an even-odd pair of FP registers) when the Status.FR bit is zero, again just like a mips64 CPU. The standard O32 ABI is defined expecting a 32-bit FPU, however recent toolchains support use of a 64-bit FPU from an O32 MIPS32 executable. When an ELF executable is built to use a 64-bit FPU a new flag (EF_MIPS_FP64) is set in the ELF header. With this patch the kernel will check the EF_MIPS_FP64 flag when executing an O32 binary, and set Status.FR accordingly. The addition of O32 64-bit FP support lessens the opportunity for optimisation in the FPU emulator, so a CONFIG_MIPS_O32_FP64_SUPPORT Kconfig option is introduced to allow this support to be disabled for those that don't require it. Inspired by an earlier patch by Leonid Yegoshin, but implemented more cleanly & correctly. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Cc: Paul Burton <paul.burton@imgtec.com> Patchwork: https://patchwork.linux-mips.org/patch/6154/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org> |
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| .. | ||
| cp1emu.c | ||
| dp_add.c | ||
| dp_cmp.c | ||
| dp_div.c | ||
| dp_fint.c | ||
| dp_flong.c | ||
| dp_frexp.c | ||
| dp_fsp.c | ||
| dp_logb.c | ||
| dp_modf.c | ||
| dp_mul.c | ||
| dp_scalb.c | ||
| dp_simple.c | ||
| dp_sqrt.c | ||
| dp_sub.c | ||
| dp_tint.c | ||
| dp_tlong.c | ||
| dsemul.c | ||
| ieee754.c | ||
| ieee754.h | ||
| ieee754d.c | ||
| ieee754dp.c | ||
| ieee754dp.h | ||
| ieee754int.h | ||
| ieee754m.c | ||
| ieee754sp.c | ||
| ieee754sp.h | ||
| ieee754xcpt.c | ||
| kernel_linkage.c | ||
| Makefile | ||
| sp_add.c | ||
| sp_cmp.c | ||
| sp_div.c | ||
| sp_fdp.c | ||
| sp_fint.c | ||
| sp_flong.c | ||
| sp_frexp.c | ||
| sp_logb.c | ||
| sp_modf.c | ||
| sp_mul.c | ||
| sp_scalb.c | ||
| sp_simple.c | ||
| sp_sqrt.c | ||
| sp_sub.c | ||
| sp_tint.c | ||
| sp_tlong.c | ||