Learning PSP assembly

[Yugisokubodai]

@TkSilver, LunaMoo: Thank you for replying me. I'm a Windows user.

As LunaMoo pointed out, I don't intend to make PSP games, but to hack/mod them. That's why I'm asking about the Asm things. Honestly, I have fundamental basic Asm with the Nes and Snes, and some PSX's Mips asm. Learning Assembly itself is not very difficult, but the key is to know clearly about the hardware of the platform. For PSP hardware, my search through the net resulted in vain.

So allow me to ask something about the PPSSPP debugger for more clarity for how the psp works. Maybe emulators are not as exact as the real hardware, but they're great helps for learning.

Let say, I'm debugging the PSP game: Dead or Alive.
Its main data contained in this file:

\PSP_GAME\USRDIAR\doap.arc

This file starts at LBA 250352 and ends at 428333. Each LBA is 2048 bytes in length, so we can say the file starts at: 250352 x 2048 = 512720896 = 0x1E8F8000.

Inside doap.arc are many texture (gim) files, including the font texture.
Now the opening screen and its GE debug looks like this.

(Imgur)
j0QNHu4.png

It says in the yellow circle: Texture L0: 0x091d1c00 (512x512) and 0x211C40 in red one.
The first font data found in doap.arc starts at these addresses:

$F00
$41100
$81300
$C1500

Which equivalent to ISO addresses:

$1E8F8F00
$1E939100
$1E979300
$1E9B9500


I want to ask as following:

1. What is L0?
2. The current texture (font 1) is loaded from 0x091d1c00? This is address is physical memory according to the PSP memory map. Is
0x091d1c00 an address in UMD?
3. Is 0x211C40 the next step to be loaded address of the next texture? Then somehow it becomes 0x09211c40.
4. Assume that I don't know where address of font 1 in doap.arc, so how to find its address with the clue: 0x091d1c00?
5. Is there any log function for PPSSPP? I mean log to text file.

Sorry for long post.