Memcpy

[MisakaMikoto]

You are free to decide which implementation to use when programming (link to which library / object), so this is a doc on that.

For those who have no idea of that function:

• C library function - memcpy()
• memcpy(3) - Linux man page

Entry address in GBAFE

• FE6: 809F990
• FE7J: 80C0ADC
• FE7U: 80BFF98
• FE8J: 80D6908
• FE8U: 80D1C0C

Note:
It is the same implementation as that in newlib.

C implementation examples for platform independency

• newlib
• glibc
• uClibc
• libgcc

Assembly implementation examples for CPU level optimization

• ARMv7-A
• Cortex-M3/M4

Note:
arm-none-eabi tool chain uses newlib, and it doesn’t have an assembly optimization for ARMv4T used in GBA:
newlib-3.0.0# find . -name ‘memcpy*’ | grep arm
./newlib/libc/machine/arm/memcpy-armv7m.S
./newlib/libc/machine/arm/memcpy-armv7a.S
./newlib/libc/machine/arm/memcpy-stub.c
./newlib/libc/machine/arm/memcpy.S

GBA platform memory copy functions

• BIOS functions
  • libtonc
  • libgba
  • libagb
    • AgbSystemCall
    • AgbSyscallDefine
    • AgbSyscallDefineArm
    • AgbMacro
• DMA
  • libtonc
  • libgba
  • libagb
    • AgbMacro

Note:

• libtonc and libgba come with devkitpro
• libagb come with Nintendo AGB SDK

Compiler doc

• GCC
  • Copying Strings and Arrays
• ARMCC
  • How do the ARM Compilers handle memcpy()
  • How does the ARM Compiler support unaligned accesses?

Discussion blogs

• memcpy and memset replacements for GBA/NDS
• Fast memcpy in C