Hi, The hardware multiplier works as defined by С standard.
As far as I understand the following code will do what you need: uint16_t a,b,c; ....... a=((uint32_t)b*c)/0x7000; 116 000a 9242 0000 mov &b, &__MPY 116 3001 117 0010 9242 0000 mov &c, &__OP2 117 3801 118 0016 1E42 3A01 mov &__RESLO, r14 119 001a 1F42 3C01 mov &__RESHI, r15 120 001e 3241 pop r2 121 0020 0C4E mov r14, r12 122 0022 0D4F mov r15, r13 123 0024 3A40 0070 mov #llo(28672), r10 124 0028 0B43 mov #lhi(28672), r11 125 002a B012 0000 call #__udivmodsi4 All the best ! Oleg Skydan http://skydan.in.ua/SOS/ ----- Original Message ----- From: penguinfly To: mspgcc-users@lists.sourceforge.net Sent: Sunday, April 30, 2006 10:55 AM Subject: Re: Re: [Mspgcc-users] How the hardware multiplier work in the mspgcc? Hi,Steven Johnson: I changed the type of varc to uint32_t, but it is also doing wrong. did you test it ? Steven Johnson <sjohn...@neurizon.net> 写道： Hi It is a bug in your code. You are assigning the result to a 16 bit quantity, so it is doing the right job. Change the type of varc to uint32_t. Steven penguinfly wrote: > Hi,everybody: > Excuse me! English is not my first language. I'm chinese. > It is hard to express my meanings clearly with my poor english. > I lvoe the mspgcc, but there are some troubles When I useing > 16-bit multiplication in f147 and fe427. The result of the 16-bit > multiplication should be 32-bit, but the compiler only read > the register 0x013a(RESLO). Is this a bug or something wrong > when i useing the hardware multiplier? > By the way, is it necessary to add "#define __msp430_have_fll" > in msp430xE42x.h? > (mspgcc-20060407,win2000/xp) > mian.c: > uint16_t vara,varb,varc; > void dispLED(uint16_t); > ... > int main(void) > { > ... > vara=0x6000; > varb=0x5000; > varc = varb * vara / 0x7000; > dispLED(varc); > ... > } > > Part of the Assemble List: > vara=0x6000; > > 81bc: b2 40 00 60 mov #24576, &0x020c ;#0x6000 > 81c0: 0c 02 > varb=0x5000; > > 81c2: b2 40 00 50 mov #20480, &0x0208 ;#0x5000 > 81c6: 08 02 > varc = varb * vara / 0x7000; > > 81c8: 02 12 push r2 ; > 81ca: 32 c2 dint > 81cc: 03 43 nop > 81ce: b2 40 00 50 mov #20480, &0x0132 ;#0x5000 > 81d2: 32 01 > 81d4: b2 40 00 60 mov #24576, &0x0138 ;#0x6000 > 81d8: 38 01 > *81da: 1f 42 3a 01 mov &0x013a,r15 ;0x013a > * 81de: 32 41 pop r2 ; > 81e0: 0c 4f mov r15, r12 ; > 81e2: 3a 40 00 70 mov #28672, r10 ;#0x7000 > 81e6: b0 12 dc 82 call #-32036 ;#0x82dc > 81ea: 0f 4c mov r12, r15 ; > 81ec: 82 4c 0a 02 mov r12, &0x020a ; > dispLED(varc); > > 81f0: b0 12 7a 81 call #-32390 ;#0x817a > > ------------------------------------------------------------------------ > 雅虎1G免费邮箱百分百防垃圾信 > 雅虎助手-搜索、杀毒、防骚扰 ------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Mspgcc-users mailing list Mspgcc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mspgcc-users ------------------------------------------------------------------------------ 无限容量雅虎相册，原图等大下载，超快速度，赶快抢注！
