FreeCalypso > hg > freecalypso-tools

annotate target-utils/libbase/osmodelay.S @ 609:ffd606adb039

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CHANGES: libserial ASYNC_LOW_LATENCY change documented
author Mychaela Falconia <falcon@freecalypso.org>
date Sat, 22 Feb 2020 19:07:46 +0000
parents e7502631a0f9
children
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1 /*
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2 * This assembly module provides a replica of OsmocomBB's bogo-millisecond
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3 * delay_ms() function. It is literally a copy of what OsmocomBB's delay_ms()
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4 * compiles to with their gcc version and their optimization settings, as seen
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5 * by doing arm-elf-objdump on their lib/delay.o.
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6 *
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7 * This hack is intended for those cases where we have to copy OsmocomBB's
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8 * black magic voodoo operations with no ability to understand what is actually
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9 * needed, such as SPCA552E initialization on the Pirelli DP-L10.
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10 */
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11
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12 .text
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13 .code 32
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14 .globl osmo_delay_ms
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15 osmo_delay_ms:
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16 mov r3, #0
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17 sub sp, sp, #4
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18 str r3, [sp]
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19 ldr r3, =1300
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20 mul r3, r0, r3
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21 b 2f
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22 1: ldr r2, [sp]
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23 ldr r2, [sp]
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24 add r2, r2, #1
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25 str r2, [sp]
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26 2: ldr r2, [sp]
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27 cmp r2, r3
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28 bcc 1b
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29 add sp, sp, #4
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30 bx lr