The advanced load address table (ALAT) is a functional unit in the Intel Itanium processor architecture. It is implemented with an associative memory. The ALAT is used to store information related to advance load instructions, as part of the speculative execution process. An "advanced load" is a method aimed in reducing the latency of costly load operations.
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The graph-coloring allocation has three major drawbacks. First, it relies on graph-coloring, which is an NP-complete problem, to decide which variables are spilled. Finding a minimal coloring graph is indeed an NP-complete problem. Second, unless live-range splitting is used, evicted variables are spilled everywhere: store (respectively load) instructions are inserted as early (respectively late) as possible, i.e.
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MIPS I has instructions that load and store 8-bit bytes, 16-bit halfwords, and 32-bit words. Only one addressing mode is supported: base + displacement. Since MIPS I is a 32-bit architecture, loading quantities fewer than 32 bits requires the datum to be either signed- or zero-extended to 32 bits. The load instructions suffixed by "unsigned" perform zero extension; otherwise sign extension is performed.
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Instructions were of 1, 2 or 3 syllables. Most arithmetic took place at the top of the Nest and used zero-address, 1-syllable instructions, although address arithmetic and index updating were handled separately in the Q store. Q Store handling, and some memory reference instructions used 2 syllables. Memory reference instructions with a 16-bit address offset, most jump instructions, and 16-bit literal load instructions, all used 3 syllables.
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To support efficient unaligned memory accesses, there are load/store word instructions suffixed by "left" or "right". All load instructions are followed by a load delay slot. The instruction in the load delay slot cannot use the data loaded by the load instruction. The load delay slot can be filled with an instruction that is not dependent on the load; a nop is substituted if such an instruction cannot be found.
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Some computer architectures have conditional instructions (such as ARM, but no longer for all instructions in 64-bit mode) or conditional load instructions (such as x86) which can in some cases make conditional branches unnecessary and avoid flushing the instruction pipeline. An instruction such as a 'compare' is used to set a condition code, and subsequent instructions include a test on that condition code to see whether they are obeyed or ignored.
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Load instructions source the base from the contents of a GPR (rs) and write the result to another GPR (rt). Store instructions source the base from the contents of a GPR (rs) and the store data from another GPR (rt). All load and store instructions compute the memory address by summing the base with the sign-extended 16-bit immediate. MIPS I requires all memory accesses to be aligned to their natural word boundaries, otherwise an exception is signaled.
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When executing a benchmark program, most of the instruction path length is typically inside the program's inner loop. Before the introduction of caches, the path length was an approximation of running time, but in modern CPUs with caches, it can be a much worse approximation, with some load instructions taking hundreds of cycles when the data is not in cache, or orders of magnitude faster when in cache (even the same instruction in another round in a loop).
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Starting with Barcelona-based processors, AMD introduced the SSE4a instruction set, which has 4 SSE4 instructions and 4 new SSE instructions. These instructions are not found in Intel's processors supporting SSE4.1 and AMD processors only started supporting Intel's SSE4.1 and SSE4.2 (the full SSE4 instruction set) in the Bulldozer-based FX processors. With SSE4a the misaligned SSE feature was also introduced which meant unaligned load instructions were as fast as aligned versions on aligned addresses. It also allowed disabling the alignment check on non-load SSE operations accessing memory.
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The PPU is an in-order processor, but it has some unique traits which allow it to achieve some benefits of out-of-order execution without expensive re-ordering hardware. Upon reaching an L1 cache miss - it can execute past the cache miss, stopping only when an instruction is actually dependent on a load. It can send up to 8 load instructions to the L2 cache out-of-order. It has an instruction delay pipe - a side path that allows it to execute instructions that would normally cause pipeline stalls without holding up the rest of the pipeline.
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But its maximum number of "erase and write" cycles were 16 counts. In 1998, NEC strategically started to expand V850 product line both in standard and ASSP business and in ASIC and SoC business. The first generation of V850 does not have unsigned load instructions, which was removed from V810 (as IN.H and IN.B), then it was added again as LD.HU and LD.BU in the second generation; V850E (V850E1) Series. In addition, V850E has some other user- friendly CISCy extensions such as "call table," "switch," and "prepare/dispose". In 2001, NEC launched V850ES core, which is ultra-low-power series, but is ISA compatible with V850E.
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The belt is fixed length and may be too short to hold all live transient operands before they are pushed off the end. If an operand is needed for longer than its belt lifetime, it must be saved while still on the belt (spill) and later restored to the belt when needed again (fill). This situation is equivalent to the need to spill registers to memory when a program runs out of registers in a general-register machine. Spilled operands may be written to memory using normal store instructions, and restored using normal load instructions, or spill and fill may use special-purpose storage and associated operations that are faster or offer other advantages over load and store.
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With this technique, load instructions that have executed out-of-order are re-executed (they access the memory system and read the value from their address a second time) when they reach the retirement point. Since the load is now the retiring instruction, it has no dependencies on any instruction still in-flight; all stores ahead of it have committed their values to the memory system, and so any value read from the memory system is guaranteed to be correct. The value read from memory at re-execution time is compared to the value obtained when the load first executed. If the values are the same, the original value was correct and no violation has occurred.
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With all 512 diodes in place, the memory contained all "one" bits; the card was programmed by cutting off each diode whose bit was to be "zero". DEC also sold versions of the card, the BM792-Yx series, pre-programmed for many standard input devices by simply omitting the unneeded diodes. Following the older approach, the earlier PDP-1 has a hardware loader, such that an operator need only push the "load" switch to instruct the paper tape reader to load a program directly into core memory. The Data General Supernova used front panel switches to cause the computer to automatically load instructions into memory from a device specified by the front panel's data switches, and then jump to loaded code; the Nova 800 and 1200 had a switch that loaded a program into main memory from a special read- only memory and jumped to it.
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