diff options
| -rw-r--r-- | disk/part.c | 28 |
1 files changed, 23 insertions, 5 deletions
diff --git a/disk/part.c b/disk/part.c index b6bae1794..3ba88c7e8 100644 --- a/disk/part.c +++ b/disk/part.c @@ -109,14 +109,31 @@ block_dev_desc_t *get_dev(char* ifname, int dev) /* * reports device info to the user */ -void dev_print (block_dev_desc_t *dev_desc) -{ + #ifdef CONFIG_LBA48 - uint64_t lba512; /* number of blocks if 512bytes block size */ +typedef uint64_t lba512_t; #else - lbaint_t lba512; +typedef lbaint_t lba512_t; #endif +/* + * Overflowless variant of (block_count * mul_by / div_by) + * when div_by > mul_by + */ +static lba512_t lba512_muldiv (lba512_t block_count, lba512_t mul_by, lba512_t 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; +} + +void dev_print (block_dev_desc_t *dev_desc) +{ + lba512_t lba512; /* number of blocks if 512bytes block size */ + if (dev_desc->type == DEV_TYPE_UNKNOWN) { puts ("not available\n"); return; @@ -184,8 +201,9 @@ void dev_print (block_dev_desc_t *dev_desc) lba = dev_desc->lba; lba512 = (lba * (dev_desc->blksz/512)); - mb = (10 * lba512) / 2048; /* 2048 = (1024 * 1024) / 512 MB */ /* round to 1 digit */ + mb = lba512_muldiv(lba512, 10, 2048); /* 2048 = (1024 * 1024) / 512 MB */ + mb_quot = mb / 10; mb_rem = mb - (10 * mb_quot); |