82 lines
3.5 KiB
Text
82 lines
3.5 KiB
Text
/* ARM assembly Raspberry PI */
|
|
/* program jensen.s */
|
|
/* compil as with option -mcpu=<processor> -mfpu=vfpv4 -mfloat-abi=hard */
|
|
/* link with gcc */
|
|
|
|
/* Constantes */
|
|
.equ EXIT, 1 @ Linux syscall
|
|
/* Initialized data */
|
|
.data
|
|
|
|
szFormat: .asciz "Result = %.8f \n"
|
|
.align 4
|
|
|
|
/* UnInitialized data */
|
|
.bss
|
|
|
|
/* code section */
|
|
.text
|
|
.global main
|
|
main:
|
|
mov r0,#1 @ first indice
|
|
mov r1,#100 @ last indice
|
|
adr r2,funcdiv @ address function
|
|
bl funcSum
|
|
vcvt.f64.f32 d1, s0 @ conversion double float for print by C
|
|
ldr r0,iAdrszFormat @ display format
|
|
vmov r2,r3,d1 @ parameter function printf for float double
|
|
bl printf @ display float double
|
|
|
|
100: @ standard end of the program
|
|
mov r0, #0 @ return code
|
|
mov r7, #EXIT @ request to exit program
|
|
svc 0 @ perform system call
|
|
|
|
iAdrszFormat: .int szFormat
|
|
/******************************************************************/
|
|
/* function sum */
|
|
/******************************************************************/
|
|
/* r0 contains begin */
|
|
/* r1 contains end */
|
|
/* r2 contains address function */
|
|
|
|
/* r0 return result */
|
|
funcSum:
|
|
push {r0,r3,lr} @ save registers
|
|
mov r3,r0
|
|
mov r0,#0 @ init r0
|
|
vmov s3,r0 @ and s3
|
|
vcvt.f32.s32 s3, s3 @ convert in float single précision (32bits)
|
|
1: @ begin loop
|
|
mov r0,r3 @ loop indice -> parameter function
|
|
blx r2 @ call function address in r2
|
|
vadd.f32 s3,s0 @ addition float
|
|
add r3,#1 @ increment indice
|
|
cmp r3,r1 @ end ?
|
|
ble 1b @ no loop
|
|
vmov s0,s3 @ return float result in s0
|
|
|
|
100:
|
|
pop {r0,r3,lr} @ restaur registers
|
|
bx lr @ return
|
|
/******************************************************************/
|
|
/* compute 1/r0 */
|
|
/******************************************************************/
|
|
/* r0 contains the value */
|
|
/* r0 return result */
|
|
funcdiv:
|
|
push {r1,lr} @ save registers
|
|
vpush {s1} @ save float registers
|
|
cmp r0,#0 @ division by zero -> end
|
|
beq 100f
|
|
ldr r1,fUn @ load float constant 1.0
|
|
vmov s0,r1 @ in float register s3
|
|
vmov s1,r0 @
|
|
vcvt.f32.s32 s1, s1 @conversion in float single précision (32 bits)
|
|
vdiv.f32 s0,s0,s1 @ division 1/r0
|
|
@ and return result in s0
|
|
100:
|
|
vpop {s1} @ restaur float registers
|
|
pop {r1,lr} @ restaur registers
|
|
bx lr @ return
|
|
fUn: .float 1
|