title 'sin' ; this subroutine generates a sin value given an argument ; the argument will be in the form of an integer from +-32767 ; where 0 is 0 radians, and 32767 is 32767*pi/32768 radians ; ; argument is passed in ax ; sin value is returned in ax ; integer value returned is abs(sin(x)*65536) if negflg is non-zero, ; then this unsigned integer is really negative ; note that an inaccurate result occurs for 90 deg, since 1. cannot be ; represented. _MODEL equ include model.inc public negflg public sin public cos public ssin public scos atnseg segment para 'horseshit' sintbl dw 0 dw 402 dw 804 dw 1206 dw 1608 dw 2010 dw 2412 dw 2814 dw 3216 dw 3617 dw 4019 dw 4420 dw 4821 dw 5222 dw 5623 dw 6023 dw 6424 dw 6824 dw 7224 dw 7623 dw 8022 dw 8421 dw 8820 dw 9218 dw 9616 dw 10014 dw 10411 dw 10808 dw 11204 dw 11600 dw 11996 dw 12391 dw 12785 dw 13180 dw 13573 dw 13966 dw 14359 dw 14751 dw 15143 dw 15534 dw 15924 dw 16314 dw 16703 dw 17091 dw 17479 dw 17867 dw 18253 dw 18639 dw 19024 dw 19409 dw 19792 dw 20175 dw 20557 dw 20939 dw 21320 dw 21699 dw 22078 dw 22457 dw 22834 dw 23210 dw 23586 dw 23961 dw 24335 dw 24708 dw 25080 dw 25451 dw 25821 dw 26190 dw 26558 dw 26925 dw 27291 dw 27656 dw 28020 dw 28383 dw 28745 dw 29106 dw 29466 dw 29824 dw 30182 dw 30538 dw 30893 dw 31248 dw 31600 dw 31952 dw 32303 dw 32652 dw 33000 dw 33347 dw 33692 dw 34037 dw 34380 dw 34721 dw 35062 dw 35401 dw 35738 dw 36075 dw 36410 dw 36744 dw 37076 dw 37407 dw 37736 dw 38064 dw 38391 dw 38716 dw 39040 dw 39362 dw 39683 dw 40002 dw 40320 dw 40636 dw 40951 dw 41264 dw 41576 dw 41886 dw 42194 dw 42501 dw 42806 dw 43110 dw 43412 dw 43713 dw 44011 dw 44308 dw 44604 dw 44898 dw 45190 dw 45480 dw 45769 dw 46056 dw 46341 dw 46624 dw 46906 dw 47186 dw 47464 dw 47741 dw 48015 dw 48288 dw 48559 dw 48828 dw 49095 dw 49361 dw 49624 dw 49886 dw 50146 dw 50404 dw 50660 dw 50914 dw 51166 dw 51417 dw 51665 dw 51912 dw 52156 dw 52398 dw 52639 dw 52878 dw 53114 dw 53349 dw 53581 dw 53812 dw 54040 dw 54267 dw 54491 dw 54714 dw 54934 dw 55152 dw 55368 dw 55582 dw 55794 dw 56004 dw 56212 dw 56418 dw 56621 dw 56823 dw 57022 dw 57219 dw 57414 dw 57607 dw 57798 dw 57986 dw 58172 dw 58356 dw 58538 dw 58718 dw 58896 dw 59071 dw 59244 dw 59415 dw 59583 dw 59750 dw 59914 dw 60075 dw 60235 dw 60392 dw 60547 dw 60700 dw 60851 dw 60999 dw 61145 dw 61288 dw 61429 dw 61568 dw 61705 dw 61839 dw 61971 dw 62101 dw 62228 dw 62353 dw 62476 dw 62596 dw 62714 dw 62830 dw 62943 dw 63054 dw 63162 dw 63268 dw 63372 dw 63473 dw 63572 dw 63668 dw 63763 dw 63854 dw 63944 dw 64031 dw 64115 dw 64197 dw 64277 dw 64354 dw 64429 dw 64501 dw 64571 dw 64639 dw 64704 dw 64766 dw 64827 dw 64884 dw 64940 dw 64993 dw 65043 dw 65091 dw 65137 dw 65180 dw 65220 dw 65259 dw 65294 dw 65328 dw 65358 dw 65387 dw 65413 dw 65436 dw 65457 dw 65476 dw 65492 dw 65505 dw 65516 dw 65525 dw 65531 dw 65535 dw 65535 atnseg ends .dataseg negflg db 0 .ends .codeseg ;assume cs:@codeseg, assume ds:@dataseg sin proc near ; main procedure mov negflg,0 test ax,7fffh ; see if zero, or -32768 jnz nok ; yup xor ax,ax ; the answer is zero ret nok: mov negflg,0 ; clear flag or ax,ax ; test the sign bit jns notsgn ; see if neg inc negflg ; leave flag neg ax ; and negate argument notsgn: test ax,16384 ; see if in outer quadrant jz nioq ; not in outer quad mov bx,ax mov ax,32768 sub ax,bx ; subtract from 32768 to switch quad nioq: mov cl,6 ; now translate 0-16384 into 0-256 mov bx,ax ; save lower 6 bits shr ax,cl shl ax,1 ; now multiply by two for word count mov si,ax assume es:atnseg push es mov ax,atnseg mov es,ax mov ax,es:[si+offset atnseg:sintbl+2] ; get next value sub ax,es:[si+offset atnseg:sintbl] ; get sin value and bx,63 ; and off important bits mul bx ; do interpolation mov bx,64 ; now divide back to scale div bx add ax,es:[si+offset atnseg:sintbl] ; now add original offset pop es assume es:nothing ret sin endp cos proc near ; guess what this routine does? add ax,16384 jmp sin cos endp .proc ssin auto ; signed sign routine push bx call sin ; call regular sin shr ax,1 ; leave room for sign information cmp negflg,0 ; should we make it negative? jz ssjp neg ax ; yes, then change sin ssjp: pop bx ret .endp .proc scos auto ; of course, man add ax,16384 jmp ssin ; did you expect any different? .endp .ends end