Let's use simple Intel and "generic PC" memory-mapping/engineered boards to get the gist of this.
BIOS/firmware is hardwired to a certain address; an address from which is immediately fetched/executed by the CPU on startup. This is the tricky part:
Is the first instruction hardwired to the CPU by memory and first executed, enabling a furthering chain of code/data execution from the first instruction itself? Or does the first instruction do something else different entirely?
Basically, when you turn the computer on and everything is fine, the first instruction for the microprocessor is mapped and "hardwired" to the CPU? Can anyone please:
1.Elaborate on what "hardwired" means in this context.
2.Explain how the process of "hardwiring" enables a finite amount of binary/electronic code burned on a semiconductor 8 inches away from the CPU gets executed the second it is turned on, and how the rest of the code gets executed after and in what order, setup, etc.?
3.How does BIOS code put its burned data from the semiconductor into RAM addresses joined by the opcodes for the CPU, and how does BIOS "intervene" and get between other processes that may be executing in parallel (examples: software interrupts, setting BARs, accessing hardware and the like etc.)?
Because look at it this way: the format/configuration of electrical voltages that make up that first instruction are local to the BIOS/firmware semiconductor. How is this arranged to work with the CPU consecutively?
BIOS/firmware is hardwired to a certain address; an address from which is immediately fetched/executed by the CPU on startup. This is the tricky part:
Is the first instruction hardwired to the CPU by memory and first executed, enabling a furthering chain of code/data execution from the first instruction itself? Or does the first instruction do something else different entirely?
Basically, when you turn the computer on and everything is fine, the first instruction for the microprocessor is mapped and "hardwired" to the CPU? Can anyone please:
1.Elaborate on what "hardwired" means in this context.
2.Explain how the process of "hardwiring" enables a finite amount of binary/electronic code burned on a semiconductor 8 inches away from the CPU gets executed the second it is turned on, and how the rest of the code gets executed after and in what order, setup, etc.?
3.How does BIOS code put its burned data from the semiconductor into RAM addresses joined by the opcodes for the CPU, and how does BIOS "intervene" and get between other processes that may be executing in parallel (examples: software interrupts, setting BARs, accessing hardware and the like etc.)?
Because look at it this way: the format/configuration of electrical voltages that make up that first instruction are local to the BIOS/firmware semiconductor. How is this arranged to work with the CPU consecutively?
Last edited: