/*
* $Xorg: stipmips.s,v 1.4 2001/02/09 02:04:39 xorgcvs Exp $
*
Copyright 1990, 1998 The Open Group
Permission to use, copy, modify, distribute, and sell this software and its
documentation for any purpose is hereby granted without fee, provided that
the above copyright notice appear in all copies and that both that
copyright notice and this permission notice appear in supporting
documentation.
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Except as contained in this notice, the name of The Open Group shall not be
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from The Open Group.
*
* Author: Keith Packard, MIT X Consortium
*/
/*
* MIPS assembly code for optimized text rendering.
*
* Other stippling could be done in assembly, but the payoff is
* not nearly as large. Mostly because large areas are heavily
* optimized already.
*/
#ifdef MIPSEL
# define BitsR sll
# define BitsL srl
# define BO(o) o
# define HO(o) o
# define WO(o) o
# define FourBits(dest,bits) and dest, bits, 0xf
#else
# define BitsR srl
# define BitsL sll
# define BO(o) 3-o
# define HO(o) 2-o
# define WO(o) o
# define FourBits(dest,bits) srl dest, bits, 28
#endif
/* reordering instructions would be fatal here */
.set noreorder
/*
* cfbStippleStack(addr, stipple, value, stride, Count, Shift)
* 4 5 6 7 16(sp) 20(sp)
*
* Apply successive 32-bit stipples starting at addr, addr+stride, ...
*
* Used for text rendering, but only when no data could be lost
* when the stipple is shifted left by Shift bits
*/
/* arguments */
#define addr $4
#define stipple $5
#define value $6
#define stride $7
#define Count 16($sp)
#define Shift 20($sp)
/* local variables */
#define count $14
#define shift $13
#define atemp $12
#define bits $11
#define lshift $9
#define sbase $8
#define stemp $2
#define CASE_SIZE 5 /* case blocks are 2^5 bytes each */
#define CASE_MASK 0x1e0 /* first case mask */
#define ForEachLine $200
#define NextLine $201
#define NextLine1 $202
#define CaseBegin $203
#define ForEachBits $204
#define ForEachBits1 $205
#define NextBits $206
#ifdef TETEXT
#define cfbStippleStack cfbStippleStackTE
#endif
.globl cfbStippleStack
.ent cfbStippleStack 2
cfbStippleStack:
.frame $sp, 0, $31
lw count, Count /* fetch stack params */
la sbase,CaseBegin /* load up switch table */
lw shift, Shift
li lshift, 4 /* compute offset within */
subu lshift, lshift, shift /* stipple of remaining bits */
#ifdef MIPSEL
addu shift, shift, CASE_SIZE /* first shift for LSB */
#else
addu shift, shift, 28-CASE_SIZE /* first shift for MSB */
#endif
/* do ... while (--count > 0) lw bits, 0(stipple) /* get stipple bits */
move atemp, addr /* set up for this line */
#ifdef TETEXT
/* Terminal emulator fonts are expanded and have many 0 rows */
beqz bits, NextLine /* skip out early on 0 */
#endif
addu addr, addr, stride /* step for the loop */
BitsR stemp, bits, shift /* get first bits */
and stemp, stemp, CASE_MASK /* compute first branch */
addu stemp, stemp, sbase /* ... */
j stemp /* ... */
BitsL bits, bits, lshift /* set remaining bits */
ForEachBits:
addu atemp, atemp, 4
ForEachBits1:
FourBits(stemp, bits) /* compute jump for */
sll stemp, stemp, CASE_SIZE /* next four bits */
addu stemp, stemp, sbase /* ... */
j stemp /* ... */
BitsL bits, bits, 4 /* step for remaining bits */
CaseBegin:
bnez bits, ForEachBits1 /* 0 */
addu atemp, atemp, 4
NextLine:
addu count, count, -1
bnez count, ForEachLine
addu stipple, stipple, 4
j $31
nop
nop
bnez bits, ForEachBits /* 1 */
sb value, BO(0)(atemp)
addu count, count, -1
bnez count, ForEachLine
addu stipple, stipple, 4
j $31
nop
nop
bnez bits, ForEachBits /* 2 */
sb value, BO(1)(atemp)
addu count, count, -1
bnez count, ForEachLine
addu stipple, stipple, 4
j $31
nop
nop
bnez bits, ForEachBits /* 3 */
sh value, HO(0)(atemp)
addu count, count, -1
bnez count, ForEachLine
addu stipple, stipple, 4
j $31
nop
nop
bnez bits, ForEachBits /* 4 */
sb value, BO(2)(atemp)
addu count, count, -1
bnez count, ForEachLine
addu stipple, stipple, 4
j $31
nop
nop
sb value, BO(0)(atemp) /* 5 */
bnez bits, ForEachBits
sb value, BO(2)(atemp)
addu count, count, -1
bnez count, ForEachLine
addu stipple, stipple, 4
j $31
nop
sb value, BO(1)(atemp) /* 6 */
bnez bits, ForEachBits
sb value, BO(2)(atemp)
addu count, count, -1
bnez count, ForEachLine
addu stipple, stipple, 4
j $31
nop
bnez bits, ForEachBits /* 7 */
swl value, BO(2)(atemp) /* untested on MSB */
addu count, count, -1
bnez count, ForEachLine
addu stipple, stipple, 4
j $31
nop
nop
bnez bits, ForEachBits /* 8 */
sb value, BO(3)(atemp)
addu count, count, -1
bnez count, ForEachLine
addu stipple, stipple, 4
j $31
nop
nop
sb value, BO(0)(atemp) /* 9 */
bnez bits, ForEachBits
sb value, BO(3)(atemp)
addu count, count, -1
bnez count, ForEachLine
addu stipple, stipple, 4
j $31
nop
sb value, BO(1)(atemp) /* a */
bnez bits, ForEachBits
sb value, BO(3)(atemp)
addu count, count, -1
bnez count, ForEachLine
addu stipple, stipple, 4
j $31
nop
sh value, HO(0)(atemp) /* b */
bnez bits, ForEachBits
sb value, BO(3)(atemp)
addu count, count, -1
bnez count, ForEachLine
addu stipple, stipple, 4
j $31
nop
bnez bits, ForEachBits /* c */
sh value, HO(2)(atemp)
addu count, count, -1
bnez count, ForEachLine
addu stipple, stipple, 4
j $31
nop
nop
sb value, BO(0)(atemp) /* d */
bnez bits, ForEachBits
sh value, HO(2)(atemp)
addu count, count, -1
bnez count, ForEachLine
addu stipple, stipple, 4
j $31
nop
bnez bits, ForEachBits /* e */
swr value, BO(1)(atemp) /* untested on MSB */
addu count, count, -1
bnez count, ForEachLine
addu stipple, stipple, 4
j $31
nop
nop
bnez bits, ForEachBits /* f */
sw value, WO(0)(atemp)
addu count, count, -1
bnez count, ForEachLine
addu stipple, stipple, 4
j $31
nop
nop
.end cfbStippleStack