FreeCalypso > hg > freecalypso-tools
view target-utils/libbase/waitarm.S @ 995:74024eb17e04
fc-loadtool help: improve language regarding 16 MiB flash chips
In FC project history, 16 MiB flash originally meant Pirelli DP-L10.
Then we got FCDEV3B with the same flash (our own design), but now we are
discovering more Calypso devices that used such large flash, both late
Calypso era (Sony Ericsson K2x0) as well as much earlier ones (FIC FLUID
devices.txt file with 2004 dates, Leonardo+ rev 5). Hence we need to
migrate to more generic or neutral language in associated documentation,
without giving elevated status to specific examples that drove our
early project history.
author | Mychaela Falconia <falcon@freecalypso.org> |
---|---|
date | Sun, 03 Dec 2023 21:11:12 +0000 |
parents | 06ad5e30e8d0 |
children |
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/* * This assembly module provides a wait_ARM_cycles() function similar to * the one in TI's firmware; it is meant to gradually replace and phase out * osmo_delay_ms(). One loop count for this function equals 4 ARM clock * cycles when running out of IRAM; if the ARM clock is 52 MHz, 13 loop counts * equal one microsecond. * * Note the instruction sequence difference from TI's firmware version: * we use the SUBS instruction (equivalent of plain SUB in Thumb) and omit * the CMP, which is why our version is 4 cycles per loop (when running * out of IRAM), as opposed to 5 cycles per loop (plus wait states as they * execute from flash) in TI's fw version. */ .text .code 32 .globl wait_ARM_cycles wait_ARM_cycles: cmp r0, #0 bxeq lr 1: subs r0, r0, #1 bne 1b bx lr