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[PATCH] ppc64: Clean up CR handling

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Make the 16550 and real mode 16550 use tail recursion like the scc code
instead of repeating the routine except for the character sent.

Gcc recoginizes the tail recursion and handles it efficently without
stack allocations.  The maple real putc shrinks from 188 to 104 bytes
of instructions.  udbg_putc drops from 188 to 140 bytes.

Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Milton Miller 2005-09-06 11:55:00 +10:00 committed by Paul Mackerras
parent 5fdabaab01
commit cb14c4d641
1 changed files with 4 additions and 12 deletions
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16
arch/ppc64/kernel/udbg.c
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@ -169,12 +169,8 @@ void udbg_maple_real_putc(unsigned char c)
while ((real_readb(&udbg_comport->lsr) & LSR_THRE) == 0) while ((real_readb(&udbg_comport->lsr) & LSR_THRE) == 0)
/* wait for idle */; /* wait for idle */;
real_writeb(c, &udbg_comport->thr); eieio(); real_writeb(c, &udbg_comport->thr); eieio();
if (c == '\n') { if (c == '\n')
/* Also put a CR. This is for convenience. */ udbg_maple_real_putc('\r');
while ((real_readb(&udbg_comport->lsr) & LSR_THRE) == 0)
/* wait for idle */;
real_writeb('\r', &udbg_comport->thr); eieio();
}
} }
} }
@ -194,12 +190,8 @@ void udbg_putc(unsigned char c)
while ((in_8(&udbg_comport->lsr) & LSR_THRE) == 0) while ((in_8(&udbg_comport->lsr) & LSR_THRE) == 0)
/* wait for idle */; /* wait for idle */;
out_8(&udbg_comport->thr, c); out_8(&udbg_comport->thr, c);
if (c == '\n') { if (c == '\n')
/* Also put a CR. This is for convenience. */ udbg_putc('\r');
while ((in_8(&udbg_comport->lsr) & LSR_THRE) == 0)
/* wait for idle */;
out_8(&udbg_comport->thr, '\r');
}
} }
#ifdef CONFIG_PPC_PMAC #ifdef CONFIG_PPC_PMAC
else if (sccc) { else if (sccc) {