Some clarifications (actually MIPS doesn't implement the float DCT/IDCT using SIMD instructions)

git-svn-id: svn://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1518 632fc199-4ca6-4c93-a231-07263d6284db

2 files changed, 10 insertions, 11 deletions

diff --git a/Makefile.am b/Makefile.am
index 309e6d6..956f30d 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -440,17 +440,18 @@ endif
 
 # The output of the floating point tests is not validated by default, because
 # the output differs depending on the type of floating point math used, and
-# this is only deterministic if there is full SIMD coverage of all of the
-# floating point algorithms in libjpeg-turbo.  Pass one of the following on the
-# make command line to validate the floating point tests against one of the
-# expected results:
+# this is only deterministic if the DCT/IDCT are implemented using SIMD
+# instructions on a particular platform.  Pass one of the following on the make
+# command line to validate the floating point tests against one of the expected # results:
 #
 # FLOATTEST=sse  validate against the expected results from the libjpeg-turbo
 #                SSE SIMD extensions
-# FLOATTEST=32bit  validate against the expected results from the MIPS DSPr2
-#                  SIMD extensions or 32-bit FPUs or GCC when -mfpmath=sse is
-#                  used (which is the default on x86-64 systems)
-# FLOATTEST=64bit  validate against the exepected results from 64-bit FPUs
+# FLOATTEST=32bit  validate against the expected results from the C code
+#                  when running on a 32-bit FPU (or when SSE is being used for
+#                  floating point math, which is generally the default with
+#                  x86-64 compilers)
+# FLOATTEST=64bit  validate against the exepected results from the C code
+#                  when running on a 64-bit FPU
 
 # CC: RGB->YCC  SAMP: fullsize/int  FDCT: float  ENT: prog huff
 	./cjpeg -sample 3x2 -dct float -prog -outfile testout_3x2_float_prog.jpg $(srcdir)/testimages/testorig.ppm
diff --git a/README-turbo.txt b/README-turbo.txt
index 1fcaedc..32b1d10 100755
--- a/README-turbo.txt
+++ b/README-turbo.txt
@@ -313,9 +313,7 @@ following reasons:
    range of the quality scale is typically more like a 1.0 dB difference.)
 -- If the floating point algorithms in libjpeg-turbo are not implemented using
    SIMD instructions on a particular platform, then the accuracy of the
-   floating point DCT/IDCT can depend on the compiler settings.  For instance,
-   different results will be obtained when using -mfpmath=387 or -mfpmath=sse
-   with GCC on x86 systems.
+   floating point DCT/IDCT can depend on the compiler settings.
 
 While libjpeg-turbo does emulate the libjpeg v8 API/ABI, under the hood, it is
 still using the same algorithms as libjpeg v6b, so there are several specific