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 98cc54db2080b78ed80479dc8c8d3e082f43dcaa..862078f3e7c8a296a1357fa112fe42a119ff2bd5 100644 (file)
--- a/disk/part.c
+++ b/disk/part.c
@@ -103,17 +103,17 @@ typedef lbaint_t lba512_t;
 #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 @@ void dev_print (struct blk_desc *dev_desc)
                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);