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| author | Michael Hayes <m.hayes@elec.canterbury.ac.nz> | 2000-07-30 08:12:12 +0000 |
|---|---|---|
| committer | Michael Hayes <m.hayes@gcc.gnu.org> | 2000-07-30 08:12:12 +0000 |
| commit | 0ea1f6b69f728ae6b87b8d0c5fc0cfbcd8b21da7 (patch) | |
| tree | 6948737ff40bd44eec2ac057bff6c63e386db935 | |
| parent | 00c9e663546bf07c2886e99b4c691727ea08020a (diff) | |
| download | gcc-0ea1f6b69f728ae6b87b8d0c5fc0cfbcd8b21da7.zip gcc-0ea1f6b69f728ae6b87b8d0c5fc0cfbcd8b21da7.tar.gz gcc-0ea1f6b69f728ae6b87b8d0c5fc0cfbcd8b21da7.tar.bz2 | |
* config/c4x/libgcc.S: (divqf3): Improve accuracy.
From-SVN: r35335
| -rw-r--r-- | gcc/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/config/c4x/libgcc.S | 25 |
2 files changed, 19 insertions, 10 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 0aeec92..a061e29 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,7 @@ +2000-07-30 Michael Hayes <m.hayes@elec.canterbury.ac.nz> + + * config/c4x/libgcc.S: (divqf3): Improve accuracy. + 2000-07-27 Mark Mitchell <mark@codesourcery.com> Put phi nodes after NOTE_INSN_BASIC_BLOCK. diff --git a/gcc/config/c4x/libgcc.S b/gcc/config/c4x/libgcc.S index 576844d..06b1a75 100644 --- a/gcc/config/c4x/libgcc.S +++ b/gcc/config/c4x/libgcc.S @@ -133,24 +133,29 @@ ___divqf3: mpyf r1, r0 ; r0 = r[2] * (2.0 - r[2] * v) = r[3] ; End of 3rd iteration - or 080h, r0 ; add 1 lsb to result. needed when complemeting - ; 1.0 / 2.0 - rnd r0 + rnd r0 ; Minimize error in x[3]'s LSBs ; Use modified last iteration ; r[4] = (r[3] * (1.0 - (v * r[3]))) + r[3] mpyf3 r0, r3, r1 ; r1 = r[3] * v subrf 1.0, r1 ; r1 = 1.0 - r[3] * v mpyf r0, r1 ; r1 = r[3] * (1.0 - r[3] * v) + addf r1, r0 ; r0 = r[3] * (1.0 - r[3] * v) + r[3] = r[4] + + rnd r0 ; Minimize error in x[4]'s LSBs bud ar1 ; Delayed branch - addf r1, r0 ; r0 = r[3] * (1.0 - r[3] * v) + r[3] = r[4] - .if .REGPARM == 0 - mpyf *-ar0(1), r0 ; Multiply by the dividend - .else - mpyf r2, r0 ; Multiply by the dividend - .endif - rnd r0 + + .if .REGPARM == 0 + ldfu *-ar0(1), r2 ; Dividend in mem has only 24 bits significance + .else + rnd r2 ; Minimize error in reg dividend's LSBs + ; since this may have 32 bit significance + .endif + + mpyf r2, r0 ; Multiply by the dividend + rnd r0 ; Round result to 32 bits + ; Branch occurs here #endif |