Would it be by way of some hard coded cpu bootrom or by way of some ROM boot loader or some embedded firmware ? Anyone ?

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    \$\begingroup\$ You should really look into how an 8088 or 8085 system boots as a basic example. Each revision of processor has added a layer of complexity but the principles are the same. If you really want to have some fun, build your own 8088 system! \$\endgroup\$ – Voltage Spike May 3 '16 at 17:13
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    \$\begingroup\$ Datasheet will describe how power-on reset is handled. Most any CPU has a predetermined starting address where the first instruction is fetched. \$\endgroup\$ – MarkU May 3 '16 at 20:09
  • \$\begingroup\$ Of course it would, why wouldnt it? you boot from some non-volatile storage, typically rom (Flash, eeprom, otp rom, whatever), because we have generally always done it that way and because it is a cheap/easy solution. \$\endgroup\$ – old_timer May 3 '16 at 23:31
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    \$\begingroup\$ I'm voting to close this question as off-topic because its not our job to read the documentation for you. \$\endgroup\$ – old_timer May 3 '16 at 23:32

The CPU is installed on a platform board along with a chipset component. The power up sequence starts with instructions from within the chipset that cause the CPU and memory power rails to come up. A power good signal is then passed to the CPU where there is an embedded controller that takes care of waking up the CPU and its cores. There is also a whole sequence of handshaking that goes on from that point that is involved with deasserting the reset of the CPU and getting its busses initialized so that it can start to fetch its first instructions (BIOS) and initialize memory and all the I/O devices.

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