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.syntax unified
.cpu cortex-m0plus
.thumb
.type whitespace, %function
.global whitespace
// 1 unexpected char
// R4 input buffer
whitespace:
LDRB R0, [R4] // get a char
CMP R0, ' // space
BEQ 1f
MOVS R0, #1 // return code 1 (unexpected char)
BX LR
1: ADDS R4, 1 // consume the character
LDRB R0, [R4] // get another character
CMP R0, ' // check if space
BEQ 1b // if so keep getting chars
MOVS R0, #0 // return code 0 (success)
BX LR
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