Lines 1213 enforce the minimum block size of 16 bytes

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Unformatted text preview: e rest of this section looks at these issues in more detail. Since the basic techniques of placement, splitting, and coalescing cut across many different free block organizations, we will introduce them in the context of a simple free block organization known as an implicit free list. 10.9.6 Implicit Free Lists Any practical allocator needs some data structure that allows it to distinguish block boundaries and to distinguish between allocated and free blocks. Most allocators embed this information in the blocks themselves. One simple approach is shown in Figure 10.37. In this case, a block consists of a one-word header, the payload, and possibly some additional padding. The header encodes the block size (including the header and any padding) as well as whether the block is allocated or free. If we impose a double-word alignment constraint, then the block size is always a multiple of eight and the three low-order bits of the block size are always zero. Thus, we need to store only the 29 high-order bits of the block size, freeing the remaining three bits to encode other information. In this case, we are using the least signiÔ¨...
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This note was uploaded on 09/02/2010 for the course ELECTRICAL 360 taught by Professor Schultz during the Spring '10 term at BYU.

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