FreeCalypso > hg > freecalypso-tools
annotate target-utils/libbase/waitarm.S @ 785:56506e9165bc
simagent: Rx data direction implemented for exchange
author | Mychaela Falconia <falcon@freecalypso.org> |
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date | Sat, 13 Mar 2021 22:17:39 +0000 |
parents | 06ad5e30e8d0 |
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rev | line source |
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453
6228d27738d1
target-utils: wait_ARM_cycles() added to libbase
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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1 /* |
495
06ad5e30e8d0
target-utils: wait_ARM_cycles() changed to 4 cycles per loop
Mychaela Falconia <falcon@freecalypso.org>
parents:
453
diff
changeset
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2 * This assembly module provides a wait_ARM_cycles() function similar to |
06ad5e30e8d0
target-utils: wait_ARM_cycles() changed to 4 cycles per loop
Mychaela Falconia <falcon@freecalypso.org>
parents:
453
diff
changeset
|
3 * the one in TI's firmware; it is meant to gradually replace and phase out |
06ad5e30e8d0
target-utils: wait_ARM_cycles() changed to 4 cycles per loop
Mychaela Falconia <falcon@freecalypso.org>
parents:
453
diff
changeset
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4 * osmo_delay_ms(). One loop count for this function equals 4 ARM clock |
06ad5e30e8d0
target-utils: wait_ARM_cycles() changed to 4 cycles per loop
Mychaela Falconia <falcon@freecalypso.org>
parents:
453
diff
changeset
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5 * cycles when running out of IRAM; if the ARM clock is 52 MHz, 13 loop counts |
06ad5e30e8d0
target-utils: wait_ARM_cycles() changed to 4 cycles per loop
Mychaela Falconia <falcon@freecalypso.org>
parents:
453
diff
changeset
|
6 * equal one microsecond. |
06ad5e30e8d0
target-utils: wait_ARM_cycles() changed to 4 cycles per loop
Mychaela Falconia <falcon@freecalypso.org>
parents:
453
diff
changeset
|
7 * |
06ad5e30e8d0
target-utils: wait_ARM_cycles() changed to 4 cycles per loop
Mychaela Falconia <falcon@freecalypso.org>
parents:
453
diff
changeset
|
8 * Note the instruction sequence difference from TI's firmware version: |
06ad5e30e8d0
target-utils: wait_ARM_cycles() changed to 4 cycles per loop
Mychaela Falconia <falcon@freecalypso.org>
parents:
453
diff
changeset
|
9 * we use the SUBS instruction (equivalent of plain SUB in Thumb) and omit |
06ad5e30e8d0
target-utils: wait_ARM_cycles() changed to 4 cycles per loop
Mychaela Falconia <falcon@freecalypso.org>
parents:
453
diff
changeset
|
10 * the CMP, which is why our version is 4 cycles per loop (when running |
06ad5e30e8d0
target-utils: wait_ARM_cycles() changed to 4 cycles per loop
Mychaela Falconia <falcon@freecalypso.org>
parents:
453
diff
changeset
|
11 * out of IRAM), as opposed to 5 cycles per loop (plus wait states as they |
06ad5e30e8d0
target-utils: wait_ARM_cycles() changed to 4 cycles per loop
Mychaela Falconia <falcon@freecalypso.org>
parents:
453
diff
changeset
|
12 * execute from flash) in TI's fw version. |
453
6228d27738d1
target-utils: wait_ARM_cycles() added to libbase
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
13 */ |
6228d27738d1
target-utils: wait_ARM_cycles() added to libbase
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
14 |
6228d27738d1
target-utils: wait_ARM_cycles() added to libbase
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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15 .text |
6228d27738d1
target-utils: wait_ARM_cycles() added to libbase
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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16 .code 32 |
6228d27738d1
target-utils: wait_ARM_cycles() added to libbase
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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17 .globl wait_ARM_cycles |
6228d27738d1
target-utils: wait_ARM_cycles() added to libbase
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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18 wait_ARM_cycles: |
6228d27738d1
target-utils: wait_ARM_cycles() added to libbase
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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19 cmp r0, #0 |
6228d27738d1
target-utils: wait_ARM_cycles() added to libbase
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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20 bxeq lr |
495
06ad5e30e8d0
target-utils: wait_ARM_cycles() changed to 4 cycles per loop
Mychaela Falconia <falcon@freecalypso.org>
parents:
453
diff
changeset
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21 1: subs r0, r0, #1 |
453
6228d27738d1
target-utils: wait_ARM_cycles() added to libbase
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
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22 bne 1b |
6228d27738d1
target-utils: wait_ARM_cycles() added to libbase
Mychaela Falconia <falcon@freecalypso.org>
parents:
diff
changeset
|
23 bx lr |