Architectures and Processors forum Initialization an array of 24-bit signed integers

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Initialization an array of 24-bit signed integers

Bushpulbek over 4 years ago

Hello, fellows!

Collided with such a task: "Using ARM assembler initialize an array of 16 elements each of one is 24-bit signed integer". We're using STM32 for calculations therefore Thumb2 instructions are only available.

Maybe anybody has an idea of what how that can be implemented?

Top replies

WestfW over 4 years ago +1 verified

store the low 16bits with STH. Then shift the register value so you can store the final 8bits with STB. Maybe preserve the original register contents. (that assumes you want code. I can also interpret...
42Bastian Schick over 4 years ago in reply to WestfW +1

Trying to solve his homework ;-) But using STH might fails on the second element. But one can split and store the lower 16bit in one table and the higher 8 bit in another. A common trick used on 6502.
WestfW over 4 years ago in reply to 42Bastian Schick +1

I thought it was a vague enough "hint" for a "do my homework" question. Good point about the 2nd element! The 6502-like trick is ... clever and gross. four stars!