L32R instruction with xtensa-esp32-elf-as assembler

[qheinal]

Im using xtensa-esp32-elf-as compiler to compile asm code but if i use the L32R instruction it compiles to 0x410000. Which means the address i specified isnt actual included in the instruction. If i use L32I it works as expected. Am i missing something?

in the code im just doing this

Code: Select all

[code]L32R a4, 0x0fc0

[/code]

im using this to compile and build flat binary

xtensa-esp32-elf-as.exe -o code.o code.asm
xtensa-esp32-elf-objcopy.exe code.o -O binary code.bin

[MicroController]

I imagine it close to impossible to "manually" write L32R instructions. After all, the R means relative to the current program counter which quickly gets impossible to track. Accordingly, the ISA summary says the syntax is "L32R at, label". So declare a label for your constant data, use it with L32R, and let the assembler calculate the correct offset.

Thinking about it, I'm not even sure if the assembler will know the offset, because 'normally' the addresses of (global) symbols are defined by the linker during linking...

[ESP_Sprite]

Decently sure MicroController hit the problem on the head. I imagine the assembler takes your 0x0fc0 argument as an absolute address (because that would correspond to putting a label there), but because the final resting place of a .o file is unknown, it can't calculate the offset between the PC and that address yet. As such, it puts a dummy value there and leaves it to the linker to fill in the real value as soon as it can be calculated.