disk: part: avoid undefined reference to `__udivmoddi4'
When compiling with FTRACE=1 an error
ld.bfd: disk/built-in.o: in function `lba512_muldiv':
disk/part.c:114: undefined reference to `__udivmoddi4
occurred.
Use '>> 11' instead of '/ 2048' to avoid the division.
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/disk/part.c b/disk/part.c
index 98cc54d..862078f 100644
--- a/disk/part.c
+++ b/disk/part.c
@@ -103,17 +103,17 @@
#endif
/*
- * Overflowless variant of (block_count * mul_by / div_by)
+ * Overflowless variant of (block_count * mul_by / 2**div_by)
* when div_by > mul_by
*/
-static lba512_t lba512_muldiv(lba512_t block_count, lba512_t mul_by, lba512_t div_by)
+static lba512_t lba512_muldiv(lba512_t block_count, lba512_t mul_by, int div_by)
{
lba512_t bc_quot, bc_rem;
/* x * m / d == x / d * m + (x % d) * m / d */
- bc_quot = block_count / div_by;
- bc_rem = block_count - div_by * bc_quot;
- return bc_quot * mul_by + (bc_rem * mul_by) / div_by;
+ bc_quot = block_count >> div_by;
+ bc_rem = block_count - (bc_quot << div_by);
+ return bc_quot * mul_by + ((bc_rem * mul_by) >> div_by);
}
void dev_print (struct blk_desc *dev_desc)
@@ -193,7 +193,7 @@
lba512 = (lba * (dev_desc->blksz/512));
/* round to 1 digit */
/* 2048 = (1024 * 1024) / 512 MB */
- mb = lba512_muldiv(lba512, 10, 2048);
+ mb = lba512_muldiv(lba512, 10, 11);
mb_quot = mb / 10;
mb_rem = mb - (10 * mb_quot);