egisin@watmath.waterloo.edu (Eric Gisin) (08/23/88)
In article <8808180442.AA08547@cory.Berkeley.EDU>, dillon@CORY.BERKELEY.EDU (Matt Dillon) writes: > In an article I write: > :copying 12 long words with movem (a0)+,regs; movem regs,(a1); add.l Rn,a1" > : takes 242 cycles on the 68000, > :while 12 successive "move.l (a0)+, (a1)+" takes 240 cycles. > :(timings derived from Motorola'a 68000 manual) > :when copying fewer words, move.l is even better. > > * BULL SHIT * > > The motorola manual states the following for movem.l: > > movem M->R, long: (An)+: 12 + 8n clock cycles > movem R->M, long: (An): 8 + 8n clock cycles > add.l D0,A1: 8 clock cycles > > Total clocks to move 12 longwords of data from source to destination > in an ascending copy is: 220 clock cycles > [asks where I got my information] Third edition of the Motorola 16-bit microprocessor user's manual. It is dated 1982. On page 203, movem r->m (long) is 8+10n cycles. I guess my sources are obsolete. Anyone know when this changed to 8+8n cycles?
mitch@Stride.COM (Thomas Mitchell) (08/26/88)
In article <20499@watmath.waterloo.edu> egisin@watmath.waterloo.edu (Eric Gisin) writes: >In article <8808180442.AA08547@cory.Berkeley.EDU>, dillon@CORY.BERKELEY.EDU (Matt Dillon) writes: >> In an article I write: >> :copying 12 long words with movem (a0)+,regs; movem regs,(a1); add.l Rn,a1" >> The motorola manual states the following for movem.l: >> >> movem M->R, long: (An)+: 12 + 8n clock cycles >> movem R->M, long: (An): 8 + 8n clock cycles >> add.l D0,A1: 8 clock cycles >> >> Total clocks to move 12 longwords of data from source to destination >> in an ascending copy is: 220 clock cycles > >Third edition of the Motorola 16-bit microprocessor user's manual. >It is dated 1982. On page 203, movem r->m (long) is 8+10n cycles. >I guess my sources are obsolete. > >Anyone know when this changed to 8+8n cycles? ^^^^^^^^^^^^^^^^^^^^^^^^^ This is a better question than at first looked! From A PRELIMINARY copy Original Issue: Sept 1, 1979 Of the MC68000 16-bit Microprocessor Users Manual page D-6 movem M->R, long: (An)+: 6 + 4n clock cycles** movem R->M, long: (An): 4 + 4n clock cycles** ** internal cycles (1 internal=2 clock input cycles) From the third edition 1982 Of the MC68000 16-bit Microprocessor Users Manual page 203 movem M->R, long: (An)+: 12 + 8n clock cycles movem R->M, long: (An): 8 +10n clock cycles From the fourth edition 1984 Of the MC68000 16/32-bit Microprocessor Users Manual page 214 movem M->R, long: (An)+: 12 + 8n clock cycles movem R->M, long: (An): 8 + 8n clock cycles A Dec 1982 manual on the 68010 and an Oct 1985 man on th 68000 hold with movem.l R->M (An): 8 + 8n clock cycles. mitch -- Thomas P. Mitchell (mitch@stride1.Stride.COM) Phone: (702)322-6868 TWX: 910-395-6073 FAX: (702)322-7975 MicroSage Computer Systems Inc. Opinions expressed are probably mine.