Consider an Intel 8086 - based system with a 16-bit external data bus. Then even
ID: 3852519 • Letter: C
Question
Consider an Intel 8086 - based system with a 16-bit external data bus. Then even bank is enabled by the signal ___ (which is active low), while the odd bank is enabled by the signal ___, which is active (low/high circle one). A word can be accessed in one memory access if the low byte is located at an (even/odd circle one) address. If not, two memory accesses would be required due to the word not being located properly, which is called ____. In fact, the cost of this is so high that the assembler and operating system will, if necessary, "stuff" an extra byte (called " ____") to make sure that the word is properly located. Regardless, if the word is not located properly, the processor will handle the issue by (halting/petting a cat/generating an interrupt/placing a Chipotle order and calling it a night/skipping the instruction circle one). The technique of locating the bytes in a word as low byte first, followed by high byte, is called___ This also implies that the address of the word is defined as the address of the (high byte/low byte circle one) in the word. The 8086's 6-byte long prefetch queue was a structure that aided processor performance as long as the instruction execution sequence was implemented (with for-next loops/circularly/random ly/linearly/using many branches circle one). Externally, the 8086 had a ___ address/data bus, which meant that the address signals and the data signals shared the same pins on the chip. This meant that the address had to be latched into external circuitry (before/after circle one) the data was on the bus. To accomplish the latching, the 8086 (and 8088) has an additional pin, called ____ to allow the external circuitry to latch in the address. Upon reset, the CS register is loaded with ___ and the instruction pointer register is loaded with ____, for a real-mode physical address of ____ hex.Explanation / Answer
Answer 1:
Consider an Intel 8086-based system with a 16 bit external data bus. The even bank is enabled by the signal A0 (which is active low),while the odd bank is enabled by the signal Bus High Enable (BHE) (which is active low). A word can be accessed in one memory access if the low byte is located at an (even) address.If not, two memory access would be required due to the word not being located properly, which is called Misalligned Word. In fact the cost of this is so high that the assembler and the operating system will, If necessary "stuff" an extra byte (called "byte padding") to make sure that the word is properly located. Regardless, If the word is not located properly, the processor will handle the issue by (generating an Interrupt). The technique of locating the byte in a word as low byte first, followed by high byte is called Little-endian. This also defines that the address of the word is defined as the address of the (low byte) in the word