i want to multiply 24bit value which i get from spi ,i stored it in an array of 3byte & i want to multiply with a constant of 8bit,the result i get which is a 32bit has to be divided with a constant of 32bit i want a c code for this procedure so pls help me
unsigned char read_val1; unsigned char read_val2; unsigned char read_val3; void send_uart(void);
void send_uart() { #pragma asm
S1 EQU 08H S2 EQU 09H S3 EQU 0AH S4 EQU 0BH
E1 EQU 0CH E2 EQU 0DH E3 EQU 0EH E4 EQU 0FH
W1 EQU 10H W2 EQU 11H W3 EQU 12H W4 EQU 13H
K1 EQU 14H K2 EQU 15H K3 EQU 16H K4 EQU 17H
CNT EQU 18H
MOV S1,#00H MOV S2,#0fH MOV S3,#42H MOV S4,#40H
MOV K1,#00H MOV K2,#00H MOV K3,#00H MOV K4,#00H mov r0, read_val1 ;h.b of n1 mov r1,read_val2 ;m.b of n1 mov r2,read_val3 ;l.b of n1 mov r7,#00h mov r6,#00h mov r5,#00h mov r4,#00h mov r3,#10h ;muliplier
mov a,r3 mov b,r2 mul ab ;product of r2r3 mov r4,a ;r3 in r4 mov r5,b ;r2 in r5 mov a,r3 mov b,r1 mul ab addc a,r5 mov r5,a mov r6,b jnc x1 mov a,r6 add a,#01 mov r6,a x1: mov a,r0 mov b,r3 mul ab add a,r6 mov r6,a mov r7,b jnc x2 mov a,r7 add a,#01 mov r7,a x2:
MOV SP,#30H
MOV E1,r7 MOV E2,r6 MOV E3,r5 MOV E4,r4
MOV CNT,#00H CALL SUB3224 JC ENDIT
DOAGAIN: INC CNT CALL SHIFTER24BITL CALL SUB3224
JNC KHALI1 CALL SHIFTER24BITR JMP LOOPBACK DEC CNT KHALI1:
MOV A,S1 JNB Acc.7,DOAGAIN
LOOPBACK: CALL SUB3224 JC BELOW MOV E1,W1 MOV E2,W2 MOV E3,W3 MOV E4,W4 ;PUT ONE SETB C MOV A,K1 RLC A MOV K1,A
MOV A,K2 RLC A MOV K2,A
MOV A,K3 RLC A MOV K3,A
MOV A,K4 RLC A MOV K4,A
CLR C ;------------- JMP OOOOO BELOW: ;PUT ZERO CLR C
MOV A,K1 ADD A,K1 MOV K1,A
OOOOO: CLR C ;------------- CALL SHIFTER24BITR DJNZ CNT,LOOPBACK RETT: JMP RETT
ENDIT: MOV K1,#00H MOV K2,#00H MOV K3,#00H MOV K4,#01H RET ;----------------- 24-bit Shifter ----------------------------- SHIFTER24BITR: ;S1:S2:S3:S4 CLR C MOV A,S1 RRC A MOV S1,A
MOV A,S2 RRC A MOV S2,A
MOV A,S3 RRC A MOV S3,A
MOV A,S4 RRC A MOV S4,A
CLR C RET
SHIFTER24BITL: MOV A,S4 ADD A,S4 ;RLC A MOV S4,A
MOV A,S3 RLC A MOV S3,A
MOV A,S2 RLC A MOV S2,A
MOV A,S1 RLC A MOV S1,A
CLR C
RET ;----------------- 32-BIT-24-BIT SUBSTARCTOR --------------------- SUB3224: ;E1:E2:E3:E4 - S1:S2:S3:S4 = W1:W2:W3:W4 CLR C MOV A,E4 SUBB A,S4 MOV W4,A
MOV A,E3 SUBB A,S3 MOV W3,A
MOV A,E2 SUBB A,S2 MOV W2,A
MOV A,E1 SUBB A,S1 MOV W1,A RET #pragma endasm return; } IS my procedure of calling inline function is correct,ifn't how to do it .also suggest me to receive values store in k1,k2,k3,k4 in c function
"IS my procedure of calling inline function is correct"
NO!
You aren't calling anything!
The entire body of the function is pure assembler - what on earth is the point in that?!
It is an assembler funcion - so put it in an Assembler file and don't mess about with the inline nonsense!
"also suggest me to receive values store in k1,k2,k3,k4 in c function"
You didn't listen last time - why should I say it again?!
You really need to leave all that as a callable assembly routine or make an earnest effort to translate it to C. Translating it shouldn't be too hard. Below is an incomplete start. Just look at what a small chunk of the code is doing, translate it to C, and iterate that (removing goto's, etc.) until you've got legitimate C.
unsigned long s, e, w, k; s = 0x000F4240; k = 0; e = read_val1; e = (e << 8) | read_val2; e = (e << 8) | read_val3; e *= 0x10; do { w = e - s; if (w < 0) goto endit; s >>= 1; : : } while ((s & 0x80000000) == 0); : : endit:
thanks a lot dan henry for your code but i don't know exact algorithm for division of 32bit/32bit no,can i put k=e/s for that or should i do it in another way if yes tell me the procedure
"can i put k=e/s for that ..."
Yes. The result of the '/' operator is the quotient from the division of the first operand by the second; the result of the '%' operator is the remainder.
mr.dan henry i am interested in knowing what the following code do
do {
w = e - s;
if (w < 0)
goto endit;
s >>= 1; : : } while ((s & 0x80000000) == 0); : : endit: i didn't understand the procedure clearly how to divide 32bit/32bit pls send me algorithm
"i am interested in knowing what the following code do"
It was only intended to illustrate my interpretation of what part of your assembly code was doing and how one might go about translating assembly to C. The ':' characters indicate that more follows but is left as an exercise for the reader (you) to complete.
"how to divide 32bit/32bit "
unsigned long dividend, divisor, quotient, remainder; quotient = dividend / divisor; remainder = dividend % divisor;
This is basic C stuff. You should try to get your hands on a C tutorial and/or reference book.