commit 968f04993b74f11763d05ffc9c3078201412cc26
parent 9ddea720055aba55b30a661e99fd344fbfcaa387
Author: afify <hassan@afify.dev>
Date: Sun, 15 Nov 2020 11:09:37 +0300
[feat] get equation of time
Diffstat:
| M | azan-nasm.s | | | 185 | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---------- |
1 file changed, 162 insertions(+), 23 deletions(-)
diff --git a/azan-nasm.s b/azan-nasm.s
@@ -7,34 +7,173 @@ BITS 64
%include "macros.s"
CHECK_OPENBSD
-section .bss
- timestamp: resb 12
- julian: resb 12
- equation_of_time: resb 12
- res_char: resb 1
- res_hour: resb 2
- res_min: resb 2
section .rodata
- julian_1970: dq 0x41429ec5c0000000 ; double 2440587.5
- sec_in_day: dq 0x40f5180000000000 ; double 86400
+ sec_inday: dq 86400.0
+ jul1970: dq 2440587.5
+ offset: dq 0xc142b42c80000000 ;double -2451545
+ to_rad: dq 0x3f91df46a2529d39 ;double pi / 180 to radian
+ to_deg: dq 0x404ca5dc1a63c1f8 ;double 180 / pi to degree
+ g_1: dq 0x3fef8a099930e901 ;double 0.98560027999999999
+ g_2: dq 0x40765876c8b43958 ;double 357.529
+ e_3: dq 0xbe9828c0be769dc1 ;double -3.5999999999999999E-7
+ e_4: dq 0x403770624dd2f1aa ;double 23.439
+ q_5: dq 0x3fef8a6c5512d6f2 ;double 0.98564735999999997
+ q_6: dq 0x4071875810624dd3 ;double 280.459
+ sing_1: dq 0x3FFEA3D70A3D70A4 ;double 1.915
+ sing_2: dq 0x3F947AE147AE147B ;double 0.020
+ RA_1: dq 0x402E000000000000 ;double 15.0
+ asin_1: dq 0x3FF0000000000000 ;double 1
+ eqt_1: dq 0x4076800000000000 ;double 360.0
+
+section .bss
+ tstamp: resb 12
+ julian: resq 1
+ EqT: resq 1
+ g: resq 1
+ g2: resq 1
+ sing: resq 1
+ sin2g: resq 1
+ sine: resq 1
+ cose: resq 1
+ sinL: resq 1
+ cosL: resq 1
+ RA_2: resq 1
+ asin_x: resq 1
section .text
global _start
- extern _printRAX
_start:
; get_timestamp:
- mov rax, SYS_gettimeofday ;sys_gettimeofday(
- mov rdi, timestamp ;struct timeval *tv,
- mov rsi, rsi ;struct timezone* tz
- syscall ;)
-
-; calc_julian:
- mov rax, [timestamp] ; mov value of timestamp in rax
- mov rbx, sec_in_day ; rbx = SEC_IN_DAY
- div rbx ; timestamp / SEC_IN_DAY
- add rax, 2440587
- mov [julian], rax ; save result of division in julian
-
- call _printRAX ;util.s
+ mov rax, SYS_gettimeofday ;sys_gettimeofday(
+ mov rdi, tstamp ;struct timeval *tv,
+ mov rsi, rsi ;struct timezone* tz
+ syscall
+
+; calc_julian:(timestamp / sec_in_day) + jul1970
+ cvtsi2sd xmm0, [tstamp] ;convert timestamp to double
+ divsd xmm0, [sec_inday] ;timestamp / sec_in_day
+ addsd xmm0, [jul1970] ;div result + jul1970
+; xmm0 = julian
+
+; calc_equation_of_time:
+ addsd xmm0, [offset] ;d = julian - offset
+; xmm0 = d
+
+ movsd xmm2, [to_rad]
+ movsd xmm1, [g_1] ;g = to_rad * ((d * 0.98560028) + 357.529)
+ mulsd xmm1, xmm0
+ addsd xmm1, [g_2]
+ mulsd xmm1, xmm2
+; xmm1 = g
+; xmm2 = to_rad
+
+ movsd xmm3, [e_3] ;e = to_rad * (23.439 - (d * 0.00000036))
+ mulsd xmm3, xmm0
+ addsd xmm3, [e_4]
+ mulsd xmm3, xmm2
+; xmm3 = e
+
+ movsd xmm4, [q_5] ;q = (d * 0.98564736) + 280.459
+ mulsd xmm4, xmm0
+ addsd xmm4, [q_6]
+; xmm4 = q
+
+; sing: ;sing = 1.915 * sin(g);
+ movsd xmm5, [sing_1]
+ finit
+ movsd [g], xmm1
+ fld qword [g]
+ fsin
+ fstp qword [sing]
+ mulsd xmm5, [sing]
+; xmm5 = sing
+
+; sin2g: ;sin2g = 0.020 * sin(2.0*g)
+ movsd xmm6, [sing_2]
+ addsd xmm1, xmm1
+ movsd [g2], xmm1
+ fld qword [g2]
+ fsin
+ fstp qword [sin2g]
+ mulsd xmm6, [sin2g]
+; xmm1 = 2 * g
+; xmm6 = sin2g
+
+; sine: ;sin(e)
+ movsd [sine], xmm3
+ fld qword [sine]
+ fsin
+ fstp qword [sine]
+
+; cose: ;cos(e)
+ movsd [cose], xmm3
+ fld qword [cose]
+ fcos
+ fstp qword [cose]
+
+; L: ;L = to_rad(q + sing + sin2g);
+ addsd xmm5, xmm6 ;sing + sin2g
+ addsd xmm5, xmm4 ;+ q
+ mulsd xmm5, xmm2 ;* to_rad
+; xmm5 = L
+
+; sinL: ;sin(L)
+ movsd [sinL], xmm5
+ fld qword [sinL]
+ fsin
+ fstp qword [sinL]
+
+; cosL: ;cos(L)
+ movsd [cosL], xmm5
+ fld qword [cosL]
+ fcos
+ fstp qword [cosL]
+
+; RA: ;RA = to_deg(atan2(cose * sinL, cosL) / 15.0);
+ movsd xmm7, [cose]
+ mulsd xmm7, [sinL]
+ movsd [cose], xmm7
+ fld qword [cose] ;load cose
+ fld qword [cosL] ;load cosL
+ fpatan ;calc atan2 (cose / cosL)
+ fstp qword [RA_2] ;save angle
+ movsd xmm7, [RA_2]
+ divsd xmm7, [RA_1] ;atan2 result /15.0
+ mulsd xmm7, [to_deg] ;* to_deg
+; xmm7 = RA
+
+; D: ;D = to_deg(asin(sine * sinL));
+; asin = arctan(x / sqrt(1 - x * x))
+ movsd xmm8, [sine]
+ mulsd xmm8, [sinL]
+ movsd [asin_x], xmm8
+ ; xmm8 = x
+
+ movsd xmm9, xmm8 ; xmm8 = x
+ mulsd xmm9, xmm8 ; xmm9 = x * x
+ movsd xmm10, [asin_1] ; xmm10 = 1
+ subsd xmm10, xmm9 ; 1 - xmm9
+ movsd [asin_1], xmm10 ; asin_1 = (1-x*x)
+ movsd [asin_x], xmm8 ; asin_1 = (1-x*x)
+; xmm9 = x * x
+; xmm10 = 1 - xmm9
+
+ fld qword [asin_x]
+ fld qword [asin_1]
+ fsqrt
+ fpatan
+ fstp qword [asin_1]
+ movsd xmm8, [asin_1]
+ mulsd xmm8, [to_deg]
+; xmm8 = D
+
+; Eqt ;EqT = q / 15.0 - RA;
+ movsd xmm9, xmm4 ; move q to xmm9
+ divsd xmm9, [RA_1] ; q / 15.0
+ subsd xmm9, xmm7 ; - RA
+; xmm9 = EqT
+; EqT = EqT - 360.0
+ subsd xmm9, [eqt_1]
+
EEXIT EXIT_SUCCESS
