Confusion related to virtual machine in nand2tetris
So while doing a course on nand2tetris I got stuck in this question.
Basically this question is related to building a virtual machine. The virtual machine is quite similar to JVM.
Solution
There are 2 main parts to consider here:
call foo 2: this instruction tells vm to call funcionfoothat takes 2 arguments ( which should be pushed on top of the stack before this call ).
Calling any function means that you should take these steps as follow: push return address on top of stack (SP++), then push LCL, ARG, THIS,THAT ( SP+4). At this point SP should equal 310.function foo 4: this is NOT the first instruction in functionfoo, but still it has an effect on SP as this means that functionfoohas 4 local variables. And these variables must be located somewhere. Where? On top of the stack. This means that before first 'real' instruction offoogets executed, we must push 4 values onto the stack. What values? Well - according do vm specification it should be0's, resulting in local variables being initiated to 0. This also means that we increase SP for every local variable ( SP + 4)
This leads to conclusion that SP, after calling foo but before executing 1st instruction of this function will have value of 314.
- How much of ‘What Every Programmer Should Know About Memory’ is still valid?
- How to assign more memory to Netbeans?
- Using "%d" to print double variable outputs differently in IA32 and IA32-64
- Using the layout of a different struct pointer
- serial memory pages (virtual memory) and TLB hit
- Memory Alignment in C/C++
- Why Linux has 4 layers of "page tables" and how it works exactly
- Alternative reasons for "out of memory" error than lack of free global memory?
- When deleting my circular linked list class, the L variable turns into random addresses
- asizeof appears to be inaccurate
- Arranging global/static objects sequentially in memory
- C++11 lambda implementation and memory model
- Do all programs need to have a stack and a heap?
- Is there a way to code data directly to the hard drive (similar to how one can do with RAM)?
- Where static objects are stored in Java?
- Visual studio 2022 highly used memory
- There is insufficient system memory in resource pool 'default' to run this query
- Python in-memory zip library
- Memory hacking / memory allocation : why does this work and how?
- Circular References Cause Memory Leak?
- memory sharing in .o file
- Why isn't my class unloaded when I erase any link to them and to ClassLoader?
- Allocating/Deallocating Memory in Rust compiled to Webassembly
- Converting .bmp to .png using powershell causes memory leak
- Optimizing low-level structure for CPU memory performance in my game simulator
- How to calculate the amount of memory occupied by the variable in Pascal?
- Debugging seeming memory issues in Python
- static variable in (embedded) C, instancing of header-file and memory consumption?
- Tensorflow Allocation Memory: Allocation of 38535168 exceeds 10% of system memory
- Does variable = null set it for garbage collection