📄 sincos.asm
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;----------------------------------------------------------------------------------------------------------
;重庆大学DSP实验室
;C函数名：void sin_cos(sincos_struct *p, int angle)
;本函数采用查表、线性插值的方法同时求
;取函数参数angle(单位：度）的正弦和余
;弦函数值，即sin(angle)、cos(angle)
;插值公式： x-x1
; y=y1+--------(y2-y1)
; x2-x1
;其中，(x1,y1),(x2,y2)分别是正弦表中
;离待求点(x,y)最近的两个已知点
;入口条件：
; 无符号整形数angle；范围：0000h～ffffh；单位：度
; 0000h <----> 0度
; 4000h <----> 90度
; 8000h <----> 180度
; c000h <----> 270度
; ffffh <----> 360度
;出口条件：
; 有符号整形数sinx,cosx；Q15；范围：0000h～ffffh
;本函数可供C语言程序调用，使用时需在main()函数前作如下定义：
; 声明外部函数：
; extern void sin_cos(sincos_struct *p, int angle) ;
; 定义全局变量保存函数返回值：
; typedef struct
; { int inv_step; ;Q15, 步长的倒数, 对于一个360点的正弦表，其步长为1度，由于
; ;1度用无符号16进制可表示成0xffff/360=182.04166667
; ;所以invstep=1/182.04166667=0.0054932=0xB4(Q15)
; int k_cosx; ;cosx=sin(x+pi/2), K_cosx=pi/2=index_max/4=360/4 for a 360 point table
; int sinx; ;Q15, 返回angle的正弦值
; int cosx; ;Q15, 返回angle的余弦值
; }sincos_struct;
;2002,3,4
;-----------------------------------------------------------------------------------------------------------
.def _sin_cos
.global _sin_cos
_sin_cos_frame .set 5h
_sin_cos:
POPD *+
SAR AR0,*+
SAR AR1,*
LAR AR0,#_sin_cos_frame
LAR AR2,*0+,AR2
LAR AR0,#2
LAR AR3,*,AR3 ;C COMPATIBLE
;STACK: angle/ *p/address/ar0/ar1
;ARP:AR3, AR2:AR1, AR3:AR1
SBRK #3
SETC SXM
LAR AR5,*-,AR5
LT *+,AR3
MPYU *,AR2
PAC
SACH *,1 ;index=floor(angle/step)
;STACK:angle/ *p/address/ar0/index
;ARP:AR2, AR2:index, AR3:angle, AR5:k_cosx
SUB *+,15
SACL *- ;Q15, K=(x-x1)/(x2-x1)=(x-x1)/step=x/step-x1/step=x/step-index
;STACK:angle/ *p/address/ar0/index/k
;ARP:AR2, AR2:index, AR3:angle, AR5:k_cosx
LACC *0+
ADD #SIN_TAB
TBLR *+ ;search for sin1
ADD #1
TBLR *+,AR5 ;search for sin2
ADD *+,AR2 ;add pi/2
TBLR *+ ;search for cos2
SUB #1
TBLR *0- ;search for cos1
;STACK:angle/ *p/address/ar0/index/k/sin1/sin2/cos2/cos1
;ARP:AR2, AR2:sin2, AR3:angle, AR5:sinx
LACC *-
SUB *+ ;sin2-sin1
SACL *0- ;STACK:angle/ *p/address/ar0/index/k/sin1/sin2-sin1/cos2/cos1
;ARP:AR2, AR2:k, AR3:angle, AR5:sinx
LT *0+
MPY *- ;kx=(x-x1)*(y2-y1)/(x2-x1)=k*(sin2-sin1)
;ARP:AR2, AR2:sin1, AR3:angle, AR5:sinx
LACC *0+,15,AR5 ;sin1-->ACC
APAC ;sinx=sin1+k*(sin2-sin1)
SACH *+,1,AR2 ;STACK:angle/ *p/address/ar0/index/k/sin1/sin2-sin1/cos2/cos1
;ARP:AR2, AR2:cos2, AR3:angle, AR5:cosx
LACC *+
SUB *-
SACL * ;cos2-cos1
MPY *+ ;K*(cos2-cos1)=(x-x1)(cos2-cos1)/(x2-x1)
LACC *,15,AR5
APAC ;cosx=cos1+(x-x1)*(cos2-cos1)/(x2-x1)
SACH *,1,AR1
SBRK #(_sin_cos_frame+1)
LAR AR0,*-
PSHD *
RET
SIN_TAB:
.word 0, 571, 1143, 1714, 2285, 2855, 3425, 3993, 4560, 5126
.word 5690, 6252, 6812, 7371, 7927, 8480, 9032, 9580, 10125, 10668
.word 11207, 11743, 12275, 12803, 13327, 13848, 14364, 14876, 15383, 15886
.word 16383, 16876, 17364, 17846, 18323, 18794, 19260, 19720, 20173, 20621
.word 21062, 21497, 21926, 22347, 22762, 23170, 23571, 23964, 24351, 24730
.word 25101, 25465, 25821, 26169, 26509, 26841, 27165, 27481, 27788, 28087
.word 28377, 28659, 28932, 29196, 29451, 29697, 29935, 30163, 30381, 30591
.word 30791, 30982, 31164, 31336, 31498, 31651, 31794, 31928, 32051, 32165
.word 32270, 32364, 32449, 32523, 32588, 32643, 32688, 32723, 32748, 32763
.word 32767, 32763, 32748, 32723, 32688, 32643, 32588, 32523, 32449, 32364
.word 32270, 32165, 32051, 31928, 31794, 31651, 31498, 31336, 31164, 30982
.word 30791, 30591, 30381, 30163, 29935, 29697, 29451, 29196, 28932, 28659
.word 28377, 28087, 27788, 27481, 27165, 26841, 26509, 26169, 25821, 25465
.word 25101, 24730, 24351, 23964, 23571, 23170, 22762, 22347, 21926, 21497
.word 21062, 20621, 20173, 19720, 19260, 18794, 18323, 17846, 17364, 16876
.word 16383, 15886, 15383, 14876, 14364, 13848, 13327, 12803, 12275, 11743
.word 11207, 10668, 10125, 9580, 9032, 8480, 7927, 7371, 6812, 6252
.word 5690, 5126, 4560, 3993, 3425, 2855, 2285, 1714, 1143, 571
.word 0, -572, -1144, -1715, -2286, -2856, -3426, -3994, -4561, -5127
.word -5691, -6253, -6813, -7372, -7928, -8481, -9033, -9581, -10126, -10669
.word -11208, -11744, -12276, -12804, -13328, -13849, -14365, -14877, -15384, -15887
.word -16385, -16877, -17365, -17847, -18324, -18795, -19261, -19721, -20174, -20622
.word -21063, -21498, -21927, -22348, -22763, -23171, -23572, -23965, -24352, -24731
.word -25102, -25466, -25822, -26170, -26510, -26842, -27166, -27482, -27789, -28088
.word -28378, -28660, -28933, -29197, -29452, -29698, -29936, -30164, -30382, -30592
.word -30792, -30983, -31165, -31337, -31499, -31652, -31795, -31929, -32052, -32166
.word -32271, -32365, -32450, -32524, -32589, -32644, -32689, -32724, -32749, -32764
.word -32767, -32764, -32749, -32724, -32689, -32644, -32589, -32524, -32450, -32365
.word -32271, -32166, -32052, -31929, -31795, -31652, -31499, -31337, -31165, -30983
.word -30792, -30592, -30382, -30164, -29936, -29698, -29452, -29197, -28933, -28660
.word -28378, -28088, -27789, -27482, -27166, -26842, -26510, -26170, -25822, -25466
.word -25102, -24731, -24352, -23965, -23572, -23171, -22763, -22348, -21927, -21498
.word -21063, -20622, -20174, -19721, -19261, -18795, -18324, -17847, -17365, -16877
.word -16384, -15887, -15384, -14877, -14365, -13849, -13328, -12804, -12276, -11744
.word -11208, -10669, -10126, -9581, -9033, -8481, -7928, -7372, -6813, -6253
.word -5691, -5127, -4561, -3994, -3426, -2856, -2286, -1715, -1144, -572
.word -1, 571, 1143, 1714, 2285, 2855, 3425, 3993, 4560, 5126
.word 5690, 6252, 6812, 7371, 7927, 8480, 9032, 9580, 10125, 10668
.word 11207, 11743, 12275, 12803, 13327, 13848, 14364, 14876, 15383, 15886
.word 16384, 16876, 17364, 17846, 18323, 18794, 19260, 19720, 20173, 20621
.word 21062, 21497, 21926, 22347, 22762, 23170, 23571, 23964, 24351, 24730
.word 25101, 25465, 25821, 26169, 26509, 26841, 27165, 27481, 27788, 28087
.word 28377, 28659, 28932, 29196, 29451, 29697, 29935, 30163, 30381, 30591
.word 30791, 30982, 31164, 31336, 31498, 31651, 31794, 31928, 32051, 32165
.word 32270, 32364, 32449, 32523, 32588, 32643, 32688, 32723, 32748, 32763
.word 32767
.end
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