Commit b6cf523c authored by Finn Thain's avatar Finn Thain Committed by Geert Uytterhoeven
Browse files

m68k: Unroll raw_outsb() loop 



Unroll the raw_outsb() loop using the optimized assembler code from
raw_outsw(). That code is copied and pasted, with movew changed to moveb.

This improves the performance of sequential write transfers using mac_esp
in PIO mode by 5% or 10%. (The DMA controller on the 840av/660av models is
still unsupported so PIO transfers are used.)

Tested-by: default avatarStan Johnson <userm57@yahoo.com>
Signed-off-by: default avatarFinn Thain <fthain@telegraphics.com.au>
Signed-off-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
parent 65102238

arch/m68k/include/asm/raw_io.h

+35 −4
Original line number Diff line number Diff line
@@ -107,12 +107,43 @@ static inline void raw_insb(volatile u8 __iomem *port, u8 *buf, unsigned int len 
}



static inline void raw_outsb(volatile u8 __iomem *port, const u8 *buf,

			     unsigned int len)

			     unsigned int nr)

{

	unsigned int i;

	unsigned int tmp;



        for (i = 0; i < len; i++)

		out_8(port, *buf++);

	if (nr & 15) {

		tmp = (nr & 15) - 1;

		asm volatile (

			"1: moveb %0@+,%2@; dbra %1,1b"

			: "=a" (buf), "=d" (tmp)

			: "a" (port), "0" (buf),

			  "1" (tmp));

	}

	if (nr >> 4) {

		tmp = (nr >> 4) - 1;

		asm volatile (

			"1: "

			"moveb %0@+,%2@; "

			"moveb %0@+,%2@; "

			"moveb %0@+,%2@; "

			"moveb %0@+,%2@; "

			"moveb %0@+,%2@; "

			"moveb %0@+,%2@; "

			"moveb %0@+,%2@; "

			"moveb %0@+,%2@; "

			"moveb %0@+,%2@; "

			"moveb %0@+,%2@; "

			"moveb %0@+,%2@; "

			"moveb %0@+,%2@; "

			"moveb %0@+,%2@; "

			"moveb %0@+,%2@; "

			"moveb %0@+,%2@; "

			"moveb %0@+,%2@; "

			"dbra %1,1b"

			: "=a" (buf), "=d" (tmp)

			: "a" (port), "0" (buf),

			  "1" (tmp));

	}

}



static inline void raw_insw(volatile u16 __iomem *port, u16 *buf, unsigned int nr)