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.syntax unified
.cpu cortex-m0plus
.thumb
.equ RESETS_BASE, 0x4000c000
.equ RESET_OFST, 0x0
.equ RESET_DONE_OFST, 0x8
.equ ATOMIC_CLEAR, 0x3000
.type setup_gpio, %function
.global setup_gpio
setup_gpio:
// clear reset
ldr r1, =(RESETS_BASE + ATOMIC_CLEAR)
movs r0, 0x20 // IO_BANK0 is bit 5
str r0, [r1, RESET_OFST]
ldr r1, =RESETS_BASE
1:
ldr r2, [r1, RESET_DONE_OFST]
tst r0, r2 // IO_BANK0 is still bit 5
// wait for reset done
beq 1b
mov pc, lr
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