kopia lustrzana https://github.com/espressif/esp-idf
freertos/xtensa_context: added infrastructure to receive the spill register optimized code
rodzic
d24fe09356
commit
d185625162
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@ -129,11 +129,18 @@ STRUCT_FIELD (long, 4, XT_STK_LEND, lend)
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STRUCT_FIELD (long, 4, XT_STK_LCOUNT, lcount)
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#endif
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#ifndef __XTENSA_CALL0_ABI__
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#ifdef CONFIG_FREERTOS_PORT_OPTIMIZE_INTERRUPT_HANDLING
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/* Todo prepare the stack frame to receive all windows regisster */
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STRUCT_FIELD (long, 4, XT_STK_TMP0, tmp0)
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STRUCT_FIELD (long, 4, XT_STK_TMP1, tmp1)
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STRUCT_FIELD (long, 4, XT_STK_TMP2, tmp2)
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#else
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/* Temporary space for saving stuff during window spill */
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STRUCT_FIELD (long, 4, XT_STK_TMP0, tmp0)
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STRUCT_FIELD (long, 4, XT_STK_TMP1, tmp1)
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STRUCT_FIELD (long, 4, XT_STK_TMP2, tmp2)
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#endif
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#endif
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#ifdef XT_USE_SWPRI
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/* Storage for virtual priority mask */
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STRUCT_FIELD (long, 4, XT_STK_VPRI, vpri)
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@ -0,0 +1,63 @@
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#ifndef __XT_ASM_UTILS_H
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#define __XT_ASM_UTILS_H
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/*
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* SPILL_ALL_WINDOWS
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*
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* Spills all windowed registers (i.e. registers not visible as
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* A0-A15) to their ABI-defined spill regions on the stack.
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*
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* Unlike the Xtensa HAL implementation, this code requires that the
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* EXCM and WOE bit be enabled in PS, and relies on repeated hardware
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* exception handling to do the register spills. The trick is to do a
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* noop write to the high registers, which the hardware will trap
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* (into an overflow exception) in the case where those registers are
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* already used by an existing call frame. Then it rotates the window
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* and repeats until all but the A0-A3 registers of the original frame
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* are guaranteed to be spilled, eventually rotating back around into
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* the original frame. Advantages:
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*
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* - Vastly smaller code size
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*
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* - More easily maintained if changes are needed to window over/underflow
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* exception handling.
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*
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* - Requires no scratch registers to do its work, so can be used safely in any
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* context.
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*
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* - If the WOE bit is not enabled (for example, in code written for
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* the CALL0 ABI), this becomes a silent noop and operates compatbily.
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*
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* - Hilariously it's ACTUALLY FASTER than the HAL routine. And not
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* just a little bit, it's MUCH faster. With a mostly full register
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* file on an LX6 core (ESP-32) I'm measuring 145 cycles to spill
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* registers with this vs. 279 (!) to do it with
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* xthal_spill_windows().
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*/
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.macro SPILL_ALL_WINDOWS
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#if XCHAL_NUM_AREGS == 64
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and a12, a12, a12
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rotw 3
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and a12, a12, a12
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rotw 3
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and a12, a12, a12
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rotw 3
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and a12, a12, a12
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rotw 3
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and a12, a12, a12
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rotw 4
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#elif XCHAL_NUM_AREGS == 32
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and a12, a12, a12
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rotw 3
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and a12, a12, a12
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rotw 3
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and a4, a4, a4
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rotw 2
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#else
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#error Unrecognized XCHAL_NUM_AREGS
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#endif
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.endm
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#endif
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@ -51,6 +51,7 @@ NOERROR: .error "C preprocessor needed for this file: make sure its filename\
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#include "xtensa_rtos.h"
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#include "xtensa_context.h"
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#include "xt_asm_utils.h"
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#ifdef XT_USE_OVLY
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#include <xtensa/overlay_os_asm.h>
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@ -143,6 +144,9 @@ _xt_context_save:
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mov a9, a0 /* preserve ret addr */
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#endif
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#ifdef CONFIG_FREERTOS_PORT_OPTIMIZE_INTERRUPT_HANDLING
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SPILL_ALL_WINDOWS /* add the optimized spill reg */
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#else
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#ifndef __XTENSA_CALL0_ABI__
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/*
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To spill the reg windows, temp. need pre-interrupt stack ptr and a4-15.
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@ -175,6 +179,7 @@ _xt_context_save:
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l32i a13, sp, XT_STK_TMP1
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l32i a9, sp, XT_STK_TMP2
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#endif
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#endif
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#if XCHAL_EXTRA_SA_SIZE > 0
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/*
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