remove expensive div in HWFIFO_ADDR_NEXT_N()

1 files changed, 12 insertions, 9 deletions

diff --git a/src/common/tusb_fifo.c b/src/common/tusb_fifo.c
index 991ee18ff..06d25d131 100644
--- a/src/common/tusb_fifo.c
+++ b/src/common/tusb_fifo.c
@@ -110,7 +110,7 @@ void tu_fifo_set_overwritable(tu_fifo_t *f, bool overwritable) {
 // Can support multiple i.e both 16 and 32-bit data access if needed
 //--------------------------------------------------------------------+
 #if CFG_TUSB_FIFO_HWFIFO_API
-  #if CFG_TUSB_FIFO_HWFIFO_ADDR_STRIDE
+  #if CFG_TUSB_FIFO_HWFIFO_ADDR_STRIDE > 0
     #define HWFIFO_ADDR_NEXT_N(_hwfifo, _const, _n) _hwfifo = (_const volatile void *)((uintptr_t)(_hwfifo) + _n)
   #else
     #define HWFIFO_ADDR_NEXT_N(_hwfifo, _const, _n)
@@ -118,6 +118,9 @@ void tu_fifo_set_overwritable(tu_fifo_t *f, bool overwritable) {
 
   #define HWFIFO_ADDR_NEXT(_hwfifo, _const) HWFIFO_ADDR_NEXT_N(_hwfifo, _const, CFG_TUSB_FIFO_HWFIFO_ADDR_STRIDE)
 
+  // the fixed ratio works since in the only case of dynamic/multiple data_stride (rusb2): addr_stride is 0
+  #define HWFIFO_ADDR_DATA_RATIO (CFG_TUSB_FIFO_HWFIFO_ADDR_STRIDE / CFG_TUSB_FIFO_HWFIFO_DATA_STRIDE)
+
 //------------- Write -------------//
   #ifndef CFG_TUSB_FIFO_HWFIFO_CUSTOM_WRITE
 TU_ATTR_ALWAYS_INLINE static inline void stride_write(volatile void *hwfifo, const void *src, uint8_t data_stride) {
@@ -235,16 +238,16 @@ void tu_hwfifo_read(const volatile void *hwfifo, uint8_t *dest, uint16_t len, co
     len -= 2;
     HWFIFO_ADDR_NEXT_N(hwfifo, const, 2);
   }
-    #endif
+      #endif
 
-    #ifdef CFG_TUSB_FIFO_HWFIFO_DATA_ODD_8BIT_ACCESS
+      #ifdef CFG_TUSB_FIFO_HWFIFO_DATA_ODD_8BIT_ACCESS
   // 8-bit access is allowed for odd bytes
   while (len > 0) {
     *dest++ = *((const volatile uint8_t *)hwfifo);
     len--;
     HWFIFO_ADDR_NEXT_N(hwfifo, const, 1);
   }
-    #else
+      #else
   // Read odd bytes i.e 1 byte for 16 bit or 1-3 bytes for 32 bit
   if (len > 0) {
     uint32_t tmp;
@@ -252,7 +255,7 @@ void tu_hwfifo_read(const volatile void *hwfifo, uint8_t *dest, uint16_t len, co
     memcpy(dest, &tmp, len);
     HWFIFO_ADDR_NEXT(hwfifo, const);
   }
-    #endif
+      #endif
     #endif
 }
   #endif
@@ -275,15 +278,15 @@ static void hwff_push_n(const tu_fifo_t *f, const void *app_buf, uint16_t n, uin
     HWFIFO_ADDR_NEXT_N(hwfifo, const, lin_bytes);
     tu_hwfifo_read(hwfifo, f->buffer, wrap_bytes, access_mode); // wrapped part
   #else
-    // Write full words to linear part of buffer
+    // Write full words to the linear part of the buffer
     const uint8_t  data_stride = access_mode->data_stride;
     const uint32_t odd_mask    = data_stride - 1;
     uint16_t       lin_even    = lin_bytes & ~odd_mask;
     tu_hwfifo_read(hwfifo, ff_buf, lin_even, access_mode);
-    HWFIFO_ADDR_NEXT_N(hwfifo, const, (lin_even / data_stride) * CFG_TUSB_FIFO_HWFIFO_ADDR_STRIDE);
+    HWFIFO_ADDR_NEXT_N(hwfifo, const, lin_even * HWFIFO_ADDR_DATA_RATIO);
     ff_buf += lin_even;
 
-    // There could be odd 1 byte (16bit) or 1-3 bytes (32bit) before the wrap-around boundary
+    // There could be an odd 1 byte (16bit) or 1-3 bytes (32bit) before the wrap-around boundary
     // combine it with the wrapped part to form a full word for data stride
     const uint8_t lin_odd = lin_bytes & odd_mask;
     if (lin_odd > 0) {
@@ -337,7 +340,7 @@ static void hwff_pull_n(const tu_fifo_t *f, void *app_buf, uint16_t n, uint16_t
     const uint32_t odd_mask    = data_stride - 1;
     uint16_t       lin_even    = lin_bytes & ~odd_mask;
     tu_hwfifo_write(hwfifo, ff_buf, lin_even, access_mode);
-    HWFIFO_ADDR_NEXT_N(hwfifo, , (lin_even / data_stride) * CFG_TUSB_FIFO_HWFIFO_ADDR_STRIDE);
+    HWFIFO_ADDR_NEXT_N(hwfifo, , lin_even * HWFIFO_ADDR_DATA_RATIO);
     ff_buf += lin_even;
 
     // There could be odd 1 byte (16bit) or 1-3 bytes (32bit) before the wrap-around boundary