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dingusppc/core/mathutils.h

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Fix TBR range Fixed an issue where TBR doesn't have full 64-bit range. The original calculation was 64 bit and ended with a ÷ 10^9. This means the max for the upper 32 bits is 2^32/10^9 = 4. The solution is to use a multiplication method that supports a 96 bit product. core/mathutils.h contains functions for that. TBR driving frequency is assumed to be less than 1 GHz. Some minor modification is required for future > 1 GHz support.
2022-09-16 04:22:37 +00:00
/*
DingusPPC - The Experimental PowerPC Macintosh emulator
Copyright (C) 2018-22 divingkatae and maximum
(theweirdo) spatium
(Contact divingkatae#1017 or powermax#2286 on Discord for more info)
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#ifndef MATH_UTILS_H
#define MATH_UTILS_H
inline void _u32xu64(uint32_t a, uint64_t b, uint32_t &hi, uint64_t &lo)
{
uint64_t p0 = (b & 0xffffffff) * a;
uint64_t p1 = (b >> 32) * a;
lo = p0 + (p1 << 32);
hi = (p1 >> 32) + (lo < p0);
}
inline void _u32xu64(uint32_t a, uint64_t b, uint64_t &hi, uint32_t &lo)
{
uint64_t p0 = (b & 0xffffffff) * a;
uint64_t p1 = (b >> 32) * a;
Fix compiler warnings: cast loses precision. Use explicit cast when converting large integer types to smaller integer types when it is known that the most significant bytes are not required. For pcidevice, check the ROM file size before casting to int. We'll allow expansion ROM sizes up to 4MB but usually they are 64K, sometimes 128K, rarely 256K. for machinefactory, change the type to size_t so that it can correctly get the size of files that are larger than 4GB; it already checks the file size is 4MB before we need to cast to uint32_t. For floppyimg, check the image size before casting to int. For raw images, only allow files up to 2MB. For DiskCopy42 images, it already checks the file size, so do the cast after that.
2022-12-21 11:20:39 +00:00
lo = (uint32_t)p0;
Fix TBR range Fixed an issue where TBR doesn't have full 64-bit range. The original calculation was 64 bit and ended with a ÷ 10^9. This means the max for the upper 32 bits is 2^32/10^9 = 4. The solution is to use a multiplication method that supports a 96 bit product. core/mathutils.h contains functions for that. TBR driving frequency is assumed to be less than 1 GHz. Some minor modification is required for future > 1 GHz support.
2022-09-16 04:22:37 +00:00
hi = (p0 >> 32) + p1;
}
inline void _u64xu64(uint64_t a, uint64_t b, uint64_t &hi, uint64_t &lo)
{
Fix compiler warnings: cast loses precision. Use explicit cast when converting large integer types to smaller integer types when it is known that the most significant bytes are not required. For pcidevice, check the ROM file size before casting to int. We'll allow expansion ROM sizes up to 4MB but usually they are 64K, sometimes 128K, rarely 256K. for machinefactory, change the type to size_t so that it can correctly get the size of files that are larger than 4GB; it already checks the file size is 4MB before we need to cast to uint32_t. For floppyimg, check the image size before casting to int. For raw images, only allow files up to 2MB. For DiskCopy42 images, it already checks the file size, so do the cast after that.
2022-12-21 11:20:39 +00:00
uint32_t p0h; uint64_t p0l; _u32xu64((uint32_t)b, a, p0h, p0l);
Fix TBR range Fixed an issue where TBR doesn't have full 64-bit range. The original calculation was 64 bit and ended with a ÷ 10^9. This means the max for the upper 32 bits is 2^32/10^9 = 4. The solution is to use a multiplication method that supports a 96 bit product. core/mathutils.h contains functions for that. TBR driving frequency is assumed to be less than 1 GHz. Some minor modification is required for future > 1 GHz support.
2022-09-16 04:22:37 +00:00
uint64_t p1h; uint32_t p1l; _u32xu64(b >> 32, a, p1h, p1l);
lo = p0l + ((uint64_t)p1l << 32);
hi = p0h + p1h + (lo < p0l);
}
#endif // MATH_UTILS_H
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