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Diffstat (limited to 'ANDROID_3.4.5/arch/alpha/lib/ev6-stxncpy.S')
| -rw-r--r-- | ANDROID_3.4.5/arch/alpha/lib/ev6-stxncpy.S | 397 |
1 files changed, 0 insertions, 397 deletions
diff --git a/ANDROID_3.4.5/arch/alpha/lib/ev6-stxncpy.S b/ANDROID_3.4.5/arch/alpha/lib/ev6-stxncpy.S deleted file mode 100644 index 1aa6e97e..00000000 --- a/ANDROID_3.4.5/arch/alpha/lib/ev6-stxncpy.S +++ /dev/null @@ -1,397 +0,0 @@ -/* - * arch/alpha/lib/ev6-stxncpy.S - * 21264 version contributed by Rick Gorton <rick.gorton@api-networks.com> - * - * Copy no more than COUNT bytes of the null-terminated string from - * SRC to DST. - * - * This is an internal routine used by strncpy, stpncpy, and strncat. - * As such, it uses special linkage conventions to make implementation - * of these public functions more efficient. - * - * On input: - * t9 = return address - * a0 = DST - * a1 = SRC - * a2 = COUNT - * - * Furthermore, COUNT may not be zero. - * - * On output: - * t0 = last word written - * t10 = bitmask (with one bit set) indicating the byte position of - * the end of the range specified by COUNT - * t12 = bitmask (with one bit set) indicating the last byte written - * a0 = unaligned address of the last *word* written - * a2 = the number of full words left in COUNT - * - * Furthermore, v0, a3-a5, t11, and $at are untouched. - * - * Much of the information about 21264 scheduling/coding comes from: - * Compiler Writer's Guide for the Alpha 21264 - * abbreviated as 'CWG' in other comments here - * ftp.digital.com/pub/Digital/info/semiconductor/literature/dsc-library.html - * Scheduling notation: - * E - either cluster - * U - upper subcluster; U0 - subcluster U0; U1 - subcluster U1 - * L - lower subcluster; L0 - subcluster L0; L1 - subcluster L1 - * Try not to change the actual algorithm if possible for consistency. - */ - -#include <asm/regdef.h> - - .set noat - .set noreorder - - .text - -/* There is a problem with either gdb (as of 4.16) or gas (as of 2.7) that - doesn't like putting the entry point for a procedure somewhere in the - middle of the procedure descriptor. Work around this by putting the - aligned copy in its own procedure descriptor */ - - - .ent stxncpy_aligned - .align 4 -stxncpy_aligned: - .frame sp, 0, t9, 0 - .prologue 0 - - /* On entry to this basic block: - t0 == the first destination word for masking back in - t1 == the first source word. */ - - /* Create the 1st output word and detect 0's in the 1st input word. */ - lda t2, -1 # E : build a mask against false zero - mskqh t2, a1, t2 # U : detection in the src word (stall) - mskqh t1, a1, t3 # U : - ornot t1, t2, t2 # E : (stall) - - mskql t0, a1, t0 # U : assemble the first output word - cmpbge zero, t2, t8 # E : bits set iff null found - or t0, t3, t0 # E : (stall) - beq a2, $a_eoc # U : - - bne t8, $a_eos # U : - nop - nop - nop - - /* On entry to this basic block: - t0 == a source word not containing a null. */ - - /* - * nops here to: - * separate store quads from load quads - * limit of 1 bcond/quad to permit training - */ -$a_loop: - stq_u t0, 0(a0) # L : - addq a0, 8, a0 # E : - subq a2, 1, a2 # E : - nop - - ldq_u t0, 0(a1) # L : - addq a1, 8, a1 # E : - cmpbge zero, t0, t8 # E : - beq a2, $a_eoc # U : - - beq t8, $a_loop # U : - nop - nop - nop - - /* Take care of the final (partial) word store. At this point - the end-of-count bit is set in t8 iff it applies. - - On entry to this basic block we have: - t0 == the source word containing the null - t8 == the cmpbge mask that found it. */ - -$a_eos: - negq t8, t12 # E : find low bit set - and t8, t12, t12 # E : (stall) - /* For the sake of the cache, don't read a destination word - if we're not going to need it. */ - and t12, 0x80, t6 # E : (stall) - bne t6, 1f # U : (stall) - - /* We're doing a partial word store and so need to combine - our source and original destination words. */ - ldq_u t1, 0(a0) # L : - subq t12, 1, t6 # E : - or t12, t6, t8 # E : (stall) - zapnot t0, t8, t0 # U : clear src bytes > null (stall) - - zap t1, t8, t1 # .. e1 : clear dst bytes <= null - or t0, t1, t0 # e1 : (stall) - nop - nop - -1: stq_u t0, 0(a0) # L : - ret (t9) # L0 : Latency=3 - nop - nop - - /* Add the end-of-count bit to the eos detection bitmask. */ -$a_eoc: - or t10, t8, t8 # E : - br $a_eos # L0 : Latency=3 - nop - nop - - .end stxncpy_aligned - - .align 4 - .ent __stxncpy - .globl __stxncpy -__stxncpy: - .frame sp, 0, t9, 0 - .prologue 0 - - /* Are source and destination co-aligned? */ - xor a0, a1, t1 # E : - and a0, 7, t0 # E : find dest misalignment - and t1, 7, t1 # E : (stall) - addq a2, t0, a2 # E : bias count by dest misalignment (stall) - - subq a2, 1, a2 # E : - and a2, 7, t2 # E : (stall) - srl a2, 3, a2 # U : a2 = loop counter = (count - 1)/8 (stall) - addq zero, 1, t10 # E : - - sll t10, t2, t10 # U : t10 = bitmask of last count byte - bne t1, $unaligned # U : - /* We are co-aligned; take care of a partial first word. */ - ldq_u t1, 0(a1) # L : load first src word - addq a1, 8, a1 # E : - - beq t0, stxncpy_aligned # U : avoid loading dest word if not needed - ldq_u t0, 0(a0) # L : - nop - nop - - br stxncpy_aligned # .. e1 : - nop - nop - nop - - - -/* The source and destination are not co-aligned. Align the destination - and cope. We have to be very careful about not reading too much and - causing a SEGV. */ - - .align 4 -$u_head: - /* We know just enough now to be able to assemble the first - full source word. We can still find a zero at the end of it - that prevents us from outputting the whole thing. - - On entry to this basic block: - t0 == the first dest word, unmasked - t1 == the shifted low bits of the first source word - t6 == bytemask that is -1 in dest word bytes */ - - ldq_u t2, 8(a1) # L : Latency=3 load second src word - addq a1, 8, a1 # E : - mskql t0, a0, t0 # U : mask trailing garbage in dst - extqh t2, a1, t4 # U : (3 cycle stall on t2) - - or t1, t4, t1 # E : first aligned src word complete (stall) - mskqh t1, a0, t1 # U : mask leading garbage in src (stall) - or t0, t1, t0 # E : first output word complete (stall) - or t0, t6, t6 # E : mask original data for zero test (stall) - - cmpbge zero, t6, t8 # E : - beq a2, $u_eocfin # U : - lda t6, -1 # E : - nop - - bne t8, $u_final # U : - mskql t6, a1, t6 # U : mask out bits already seen - stq_u t0, 0(a0) # L : store first output word - or t6, t2, t2 # E : (stall) - - cmpbge zero, t2, t8 # E : find nulls in second partial - addq a0, 8, a0 # E : - subq a2, 1, a2 # E : - bne t8, $u_late_head_exit # U : - - /* Finally, we've got all the stupid leading edge cases taken care - of and we can set up to enter the main loop. */ - extql t2, a1, t1 # U : position hi-bits of lo word - beq a2, $u_eoc # U : - ldq_u t2, 8(a1) # L : read next high-order source word - addq a1, 8, a1 # E : - - extqh t2, a1, t0 # U : position lo-bits of hi word (stall) - cmpbge zero, t2, t8 # E : - nop - bne t8, $u_eos # U : - - /* Unaligned copy main loop. In order to avoid reading too much, - the loop is structured to detect zeros in aligned source words. - This has, unfortunately, effectively pulled half of a loop - iteration out into the head and half into the tail, but it does - prevent nastiness from accumulating in the very thing we want - to run as fast as possible. - - On entry to this basic block: - t0 == the shifted low-order bits from the current source word - t1 == the shifted high-order bits from the previous source word - t2 == the unshifted current source word - - We further know that t2 does not contain a null terminator. */ - - .align 4 -$u_loop: - or t0, t1, t0 # E : current dst word now complete - subq a2, 1, a2 # E : decrement word count - extql t2, a1, t1 # U : extract low bits for next time - addq a0, 8, a0 # E : - - stq_u t0, -8(a0) # U : save the current word - beq a2, $u_eoc # U : - ldq_u t2, 8(a1) # U : Latency=3 load high word for next time - addq a1, 8, a1 # E : - - extqh t2, a1, t0 # U : extract low bits (2 cycle stall) - cmpbge zero, t2, t8 # E : test new word for eos - nop - beq t8, $u_loop # U : - - /* We've found a zero somewhere in the source word we just read. - If it resides in the lower half, we have one (probably partial) - word to write out, and if it resides in the upper half, we - have one full and one partial word left to write out. - - On entry to this basic block: - t0 == the shifted low-order bits from the current source word - t1 == the shifted high-order bits from the previous source word - t2 == the unshifted current source word. */ -$u_eos: - or t0, t1, t0 # E : first (partial) source word complete - nop - cmpbge zero, t0, t8 # E : is the null in this first bit? (stall) - bne t8, $u_final # U : (stall) - - stq_u t0, 0(a0) # L : the null was in the high-order bits - addq a0, 8, a0 # E : - subq a2, 1, a2 # E : - nop - -$u_late_head_exit: - extql t2, a1, t0 # U : - cmpbge zero, t0, t8 # E : - or t8, t10, t6 # E : (stall) - cmoveq a2, t6, t8 # E : Latency=2, extra map slot (stall) - - /* Take care of a final (probably partial) result word. - On entry to this basic block: - t0 == assembled source word - t8 == cmpbge mask that found the null. */ -$u_final: - negq t8, t6 # E : isolate low bit set - and t6, t8, t12 # E : (stall) - and t12, 0x80, t6 # E : avoid dest word load if we can (stall) - bne t6, 1f # U : (stall) - - ldq_u t1, 0(a0) # L : - subq t12, 1, t6 # E : - or t6, t12, t8 # E : (stall) - zapnot t0, t8, t0 # U : kill source bytes > null - - zap t1, t8, t1 # U : kill dest bytes <= null - or t0, t1, t0 # E : (stall) - nop - nop - -1: stq_u t0, 0(a0) # L : - ret (t9) # L0 : Latency=3 - - /* Got to end-of-count before end of string. - On entry to this basic block: - t1 == the shifted high-order bits from the previous source word */ -$u_eoc: - and a1, 7, t6 # E : avoid final load if possible - sll t10, t6, t6 # U : (stall) - and t6, 0xff, t6 # E : (stall) - bne t6, 1f # U : (stall) - - ldq_u t2, 8(a1) # L : load final src word - nop - extqh t2, a1, t0 # U : extract low bits for last word (stall) - or t1, t0, t1 # E : (stall) - -1: cmpbge zero, t1, t8 # E : - mov t1, t0 # E : - -$u_eocfin: # end-of-count, final word - or t10, t8, t8 # E : - br $u_final # L0 : Latency=3 - - /* Unaligned copy entry point. */ - .align 4 -$unaligned: - - ldq_u t1, 0(a1) # L : load first source word - and a0, 7, t4 # E : find dest misalignment - and a1, 7, t5 # E : find src misalignment - /* Conditionally load the first destination word and a bytemask - with 0xff indicating that the destination byte is sacrosanct. */ - mov zero, t0 # E : - - mov zero, t6 # E : - beq t4, 1f # U : - ldq_u t0, 0(a0) # L : - lda t6, -1 # E : - - mskql t6, a0, t6 # U : - nop - nop - subq a1, t4, a1 # E : sub dest misalignment from src addr - - /* If source misalignment is larger than dest misalignment, we need - extra startup checks to avoid SEGV. */ - -1: cmplt t4, t5, t12 # E : - extql t1, a1, t1 # U : shift src into place - lda t2, -1 # E : for creating masks later - beq t12, $u_head # U : (stall) - - extql t2, a1, t2 # U : - cmpbge zero, t1, t8 # E : is there a zero? - andnot t2, t6, t2 # E : dest mask for a single word copy - or t8, t10, t5 # E : test for end-of-count too - - cmpbge zero, t2, t3 # E : - cmoveq a2, t5, t8 # E : Latency=2, extra map slot - nop # E : keep with cmoveq - andnot t8, t3, t8 # E : (stall) - - beq t8, $u_head # U : - /* At this point we've found a zero in the first partial word of - the source. We need to isolate the valid source data and mask - it into the original destination data. (Incidentally, we know - that we'll need at least one byte of that original dest word.) */ - ldq_u t0, 0(a0) # L : - negq t8, t6 # E : build bitmask of bytes <= zero - mskqh t1, t4, t1 # U : - - and t6, t8, t12 # E : - subq t12, 1, t6 # E : (stall) - or t6, t12, t8 # E : (stall) - zapnot t2, t8, t2 # U : prepare source word; mirror changes (stall) - - zapnot t1, t8, t1 # U : to source validity mask - andnot t0, t2, t0 # E : zero place for source to reside - or t0, t1, t0 # E : and put it there (stall both t0, t1) - stq_u t0, 0(a0) # L : (stall) - - ret (t9) # L0 : Latency=3 - nop - nop - nop - - .end __stxncpy |