I was having issue to find answer for the two problems before What is the memory
ID: 3869377 • Letter: I
Question
I was having issue to find answer for the two problems before
What is the memory address range of Interrupt Vectors block (or table)?
I was not sure if this question was relating to the picture from above or down below. If the two questions from below relate to screenshot one from above. Then I think it is Data RAM/Stack. For the second screenshot, I was not able to connect the question to my created program. I need help to solve this problem and due tonight? Thank you
In which memory block does the assembly program of this lab reside?
In the program, the code STAA $1020 will store the subtraction result to memory location $1020. To which memory block does this location belong?
Registers (I/O and SFRs) 03FF 0400 EEPROM OFFF 1000 Data RAM/Stack 4000 Code ROM (Flash) 7FFF 8000 Page Window BFFF C000 Code ROM (Flash) FEFF FF00 Interrupt VectorExplanation / Answer
The first question relates to the first picture (the picture above the text). We see that out of the total of 0000 to FFFF area, FF00 to FFFF is labelled "Interrupt Vector". This is where the Interrupt Vector table resides.
The Data RAM/Stack is actually where the temporary variables and data that we use during the execution of the program are manipulated. When we say "push something onto the stack" we mean use the most recent empty location in the stack section to store that byte of data. Similarly data is "popped", i.e. taken off the stack when we need to use it in a subsequent instruction. The name of the section, "Data RAM/stack" thus implies that that section is for data, whereas vector interrupts are pre-coded hardcoded code instructions, usually placed at the very end of the storage area (FF00 to FFFF in this case).
The actual program, that is, the instructions, are saved in the "Code" section of the storage, since that is what it is, code, that is to be executed. (We want to avoid accidentally executing variables and such, so we keep separate areas in the storage defined by purpose.) The third section of the program clarifies this - the line where it says CODE EQU $4000 - this very code is saved from the location $4000 onwards, i.e. in Code ROM (Flash) (4000-7FFF).
Similarly, the instruction STAA $1020 saves the result at memory location 1020, which as we see from the partitions in the first image, is in the "Data RAM/Stack" block of the storage. This makes sense based on the explanation I gave above for what the Data RAM/Stack section is for. Hope this makes sense!
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