Add fast_div16_8 & fast_div32_16 to the public API

adbancroft · Nov 3, 2024 · 833c898 · 833c898
1 parent b2dd12e
commit 833c898
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Showing 2 changed files with 31 additions and 15 deletions.
diff --git a/src/avr-fast-div.cpp b/src/avr-fast-div.cpp
@@ -28,6 +28,16 @@
 #define AFD_PUBLICAPI_ATTTRIBUTE
 #endif
 
+uint8_t AFD_PUBLICAPI_ATTTRIBUTE fast_div16_8(uint16_t udividend, uint8_t udivisor) {
+  AFD_ZERO_DIVISOR_CHECK(udividend, udivisor);
+  return (uint8_t)avr_fast_div_impl::divide(udividend, udivisor);
+}
+
+uint16_t AFD_PUBLICAPI_ATTTRIBUTE fast_div32_16(uint32_t udividend, uint16_t udivisor) {
+  AFD_ZERO_DIVISOR_CHECK(udividend, udivisor);
+  return avr_fast_div_impl::divide(udividend, udivisor);
+}
+
 uint8_t AFD_PUBLICAPI_ATTTRIBUTE fast_div(uint8_t udividend, uint8_t udivisor) {
   AFD_ZERO_DIVISOR_CHECK(udividend, udivisor);
   // u8/u8 => u8
@@ -63,12 +73,6 @@ static inline uint32_t fast_divu32u16(uint32_t udividend, uint16_t udivisor) {
   if (udivisor > (uint16_t)(udividend >> 16U)) {
     return avr_fast_div_impl::divide(udividend, udivisor);
   }
-// Fallback to 24-bit if supported
-// #if defined(__UINT24_MAX__)
-//   if((udividend<__UINT24_MAX__)) {
-//     return (__uint24)udividend / (__uint24)udivisor;
-//   }  
-// #endif    
   // We now know that udividend > udivisor * 65536U
   // u32/u32=>u32
   return udividend / udivisor;
@@ -90,12 +94,6 @@ uint32_t AFD_PUBLICAPI_ATTTRIBUTE fast_div(uint32_t udividend, uint32_t udivisor
   if (udivisor<=(uint32_t)UINT16_MAX) {
     return fast_divu32u16(udividend, (uint16_t)udivisor);
   }
-// Fallback to 24-bit if supported
-// #if defined(__UINT24_MAX__)
-//   if((udividend<__UINT24_MAX__) && (udivisor<__UINT24_MAX__)) {
-//     return (__uint24)udividend / (__uint24)udivisor;
-//   }  
-// #endif  
   // We now know that udivisor > 65535U. I.e. upper word bits are set
   // u32/u32=>u32
   return avr_fast_div_impl::divide_large_divisor<uint32_t>(udividend, udivisor);

diff --git a/src/avr-fast-div.h b/src/avr-fast-div.h
@@ -60,10 +60,28 @@ static inline TUnsigned safe_abs(TSigned svalue) {
 
 // Public API
 
-uint8_t fast_div(uint8_t udividend, uint8_t udivisor);
-uint16_t fast_div(uint16_t udividend, uint8_t udivisor);
+/// @brief Optimized division of a 16-bit unsigned by a 8-bit unsigned with an *8-bit unsigned result*
+///
+/// @warning Should only be called if it's known that the result will fit into 8-bits
+///
+/// @param udividend Dividend
+/// @param udivisor Divisor
+/// @return udividend/udivisor
+uint8_t fast_div16_8(uint16_t udividend, uint8_t udivisor);
+
+/// @brief Optimized division of a 32-bit unsigned by a 16-bit unsigned with a *16-bit unsigned result*
+///
+/// @warning Should only be called if it's known that the result will fit into 16-bits
+///
+/// @param udividend Dividend
+/// @param udivisor Divisor
+/// @return udividend/udivisor
+uint16_t fast_div32_16(uint32_t udividend, uint16_t udivisor);
+
+uint8_t  fast_div(uint8_t  udividend, uint8_t  udivisor);
+uint16_t fast_div(uint16_t udividend, uint8_t  udivisor);
 uint16_t fast_div(uint16_t udividend, uint16_t udivisor);
-uint32_t fast_div(uint32_t udividend, uint8_t udivisor);
+uint32_t fast_div(uint32_t udividend, uint8_t  udivisor);
 uint32_t fast_div(uint32_t udividend, uint16_t udivisor);
 uint32_t fast_div(uint32_t udividend, uint32_t udivisor);