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Initial prototype for a copy_string function

This commit is contained in:
Jeremiah Orians 2016-08-14 17:41:16 -04:00
parent 8a279ecc96
commit 4ed9c427f2
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2 changed files with 42 additions and 2 deletions
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5
Library function prototypes/clear_string.s
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@ -1,4 +1,5 @@
# We will be using R0 and R1 to pass values to the function
# We will be using R0 to pass pointer to string
# to cleared by the function
# R15 will be used as the stack pointer
:start
LOADUI R0 @string
@ -29,7 +30,7 @@
LOADXU8 R0 R1 R2 ; Get the byte
STOREX8 R3 R1 R2 ; Overwrite with a Zero
ADDUI R2 R2 1 ; Prep for next loop
CMPJUMP.NE R0 R3 @clear_byte ; Stop if byte is NULL
JUMP.NZ R0 @clear_byte ; Stop if byte is NULL
;; Done
;; Restore registers
POPR R3 R15

39
Library function prototypes/copy_string.s Normal file
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@ -0,0 +1,39 @@
# We will be using R0 and R1 to pass values to the function
# R15 will be used as the stack pointer
:start
LOADUI R0 @string
LOADUI R1 0x100
LOADUI R2 33
LOADUI R3 44
LOADUI R4 55
LOADUI R15 0x600
CALLI R15 @copy_string
HALT
:string
HALT
HALT
NOP
;; Our simple string compare function
:copy_string
;; Preserve registers
PUSHR R0 R15
PUSHR R1 R15
PUSHR R2 R15
PUSHR R3 R15
;; Setup registers
MOVE R2 R1
MOVE R1 R0
LOADUI R3 0
:copy_byte
LOADXU8 R0 R1 R3 ; Get the byte
STOREX8 R0 R2 R3 ; Store the byte
ADDUI R3 R3 1 ; Prep for next loop
JUMP.NZ R0 @copy_byte ; Stop if byte is NULL
;; Done
;; Restore registers
POPR R3 R15
POPR R2 R15
POPR R1 R15
POPR R0 R15
RET R15