TCG | trading card game featuring a simple AI | Runtime Evironment library

QEMU uses a set of data structures called MemoryRegions to model the address space that a CPU sees (the detailed API is documented in part in the developer docs).

MemoryRegions can be built up into a tree, where at the "root" there is one 'container' MR which covers the whole 64-bit address space the guest CPU can see, and then MRs for blocks of RAM, devices, etc are placed into that root MR at appropriate offsets. Child MRs can also be containers which in turn contain further MRs. You can then find the MR corresponding to a given guest physical address by walking through the tree of MRs.

The tree of MemoryRegions is largely built up statically when QEMU starts (because most devices don't move around), but it can also be changed dynamically in response to guest software actions. In particular, PCI works this way. When the guest OS writes to a PCI device BAR (which is in PCI config space) this causes QEMU's PCI host controller emulation code to place the MR corresponding to the device's registers into the MemoryRegion hierarchy at the correct place and offset (depending on what address the guest wrote to the BAR, ie where it asked for it to be mapped). Once this is done, the MR for the PCI device is like any other in the tree, and the PCI host controller code doesn't need to be involved in guest accesses to it.

As a performance optimisation, QEMU doesn't actually walk down a tree of MRs for every access. Instead, we first "flatten" the tree into a data structure (a FlatView) that directly says "for this range of addresses, it will be this MR; for this range; this MR", and so on. Secondly, QEMU's TLB structure can directly cache mappings from "guest virtual address" to "specific memory region". On first access it will do an emulated guest MMU page table walk to get from the guest virtual address to the guest physical address, and then it will look that physical address up in the FlatView to find either the real host RAM or the MemoryRegion that is mapped there, and it will add the "guest VA -> this MR" mapping to the TLB cache. Future accesses will hit in the TLB and need not repeat the work of converting to a physaddr and then finding the MR in the flatmap. This is what is happening in your backtrace -- the io_readx() function is passed the guest virtual address and also the relevant part of the TLB data structure, and it can then directly find the target MR and the offset within it, so it can call memory_region_dispatch_read() to dispatch the read request to that MR's read callback function. (If this was the first access, the initial "MMU walk + FlatView lookup" work will have just been done in load_helper() before it calls io_readx().)

Obviously, all this caching also implies that QEMU tracks events which mean the cached data is no longer valid so we can throw it away (eg if the guest writes to the BAR again to unmap it or to map it somewhere else; or if the MMU settings or page tables are changed to alter the guest virtual-to-physical mapping).

I think the issue is with you mixing up variable names - your translation code appends to protein but you print output_protein which I assume is actually created somewhere else in your code(?). Also, you first edit the variable dna_sequence but iterate over dna which I assume is also defined elsewhere and maybe doesn't match dna_sequence.

After editing the variable names I can use your code to get the same translation as the NCBI tool.

First run this command

In you fiddle you have:

It's an error related SettingWithCopyWarning. It's important — read up on it here. Usually you can avoid it with .loc and by avoiding repeat-slicing, but in some cases where you have to slice repeatedly you can get around it by ending .copy() to the end of the expression. You can learn when and why this is important via the link. For a more precise answer for how this is emerging from you'll code, you'll need to show us an MRCE of your code.

use get_class($action) to get class TCG\Voyager\Actions\DeleteAction

ref link https://www.php.net/manual/en/function.get-class.php

You keep incrementing base and incrementing l but without checking if you've exceeded the length of the rna string. Changing the condition of your while loop to

on debugging the code i found out that the cards have margin property in minus

as you can see the structure.

1. the cards wrapper is moved where the dynamic desc is being appended.
2. the style: adding position: relative; and removing the margin: -(value); to the same element.

hope this helped.