fix sound on platforms where 'unsigned long' is only 32 bits wide #173
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Commit 1d5f921 introduced a bit shift that is too wide on 32 bit platforms. This results in the volume of all channels being set to zero in the internal mixer. Problem observed on a Raspberry Pi Zero W, where the compiler also complains: libgambatte/src/sound.cpp:106:63: warning: right shift count >= width of type [-Wshift-count-overflow] ch1_.update(buf, (soChVol_[0] * soVol_ * 0x1999999A) >> 32, cycles); ^~ Fix this problem by expanding the constant 0x1999999A to unsigned long long via the 'ULL' suffix. This results in all values in the expression being promoted to 'unsigned long long', which is 64 bit wide everywhere.
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Good catch. Thanks for contributing. |
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Exact same issue as explained here: #167 (comment) |
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Hi there, as per @jdgleaver's recommendation, I am reverting this PR for now until the Holidays are over, and then we can properly go over this and implement it in a way so everyone is happy and all platforms work. My bad. |
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Commit 1d5f921 introduced a bit shift
that is too wide on 32 bit platforms. This results in the volume of
all channels being set to zero in the internal mixer.
Problem observed on a Raspberry Pi Zero W, where the compiler also
complains:
libgambatte/src/sound.cpp:106:63:
warning: right shift count >= width of type [-Wshift-count-overflow]
ch1_.update(buf, (soChVol_[0] * soVol_ * 0x1999999A) >> 32, cycles);
^~
Fix this problem by expanding the constant 0x1999999A to unsigned long long
via the 'ULL' suffix. This results in all values in the expression being
promoted to 'unsigned long long', which is 64 bit wide everywhere.