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Update RISK-V GCC port to ensure the first task starts with interrupts enabled - previously its interrupts were only enabled after it yielded for the first time.

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Richard Barry 2019-10-21 04:16:32 +00:00
parent a83244a37e
commit 61a003088d
1 changed files with 7 additions and 4 deletions
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11
FreeRTOS/Source/portable/GCC/RISC-V/portASM.S
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@ -172,7 +172,7 @@ handle_asynchronous:
li t4, -1
lw t2, 0(t1) /* Load the low word of ullNextTime into t2. */
lw t3, 4(t1) /* Load the high word of ullNextTime into t3. */
sw t4, 0(t0) /* Low word no smaller than old value. */
sw t4, 0(t0) /* Low word no smaller than old value to start with - will be overwritten below. */
sw t3, 4(t0) /* Store high word of ullNextTime into compare register. No smaller than new value. */
sw t2, 0(t0) /* Store low word of ullNextTime into compare register. */
lw t0, uxTimerIncrementsForOneTick /* Load the value of ullTimerIncrementForOneTick into t0 (could this be optimized by storing in an array next to pullNextTime?). */
@ -223,11 +223,13 @@ test_if_environment_call:
j processed_source
is_exception:
ebreak
csrr t0, mcause /* For viewing in the debugger only. */
csrr t1, mepc /* For viewing in the debugger only */
csrr t2, mstatus
j is_exception
as_yet_unhandled:
ebreak
csrr t0, mcause /* For viewing in the debugger only. */
j as_yet_unhandled
processed_source:
@ -298,6 +300,7 @@ xPortStartFirstTask:
portasmRESTORE_ADDITIONAL_REGISTERS /* Defined in freertos_risc_v_chip_specific_extensions.h to restore any registers unique to the RISC-V implementation. */
load_x t0, 29 * portWORD_SIZE( sp ) /* mstatus */
addi t0, t0, 0x08 /* Set MIE bit so the first task starts with interrupts enabled - required as returns with ret not eret. */
csrrw x0, mstatus, t0 /* Interrupts enabled from here! */
load_x x5, 2 * portWORD_SIZE( sp ) /* t0 */
@ -399,7 +402,7 @@ xPortStartFirstTask:
pxPortInitialiseStack:
csrr t0, mstatus /* Obtain current mstatus value. */
addi t1, x0, 0x188 /* Generate the value 0x1880, which are the MPIE and MPP bits to set in mstatus. */
addi t1, x0, 0x188 /* Generate the value 0x1888, which are the MIE, MPIE and privilege bits to set in mstatus. */
slli t1, t1, 4
or t0, t0, t1 /* Set MPIE and MPP bits in mstatus value. */