AN2203 Freescale Semiconductor / Motorola, AN2203 Datasheet - Page 56

• Manufacturer Part Number: AN2203
• Description: MPC7450 RISC Microprocessor Family Software Optimization Guide
• Manufacturer: Freescale Semiconductor / Motorola

Negated Comparisons and Negated Comparisons Against Zero
56
neq
r = -(v0 == v1)
nne
r = -(v0 != v1)
nles/nges
r = -((signed_word) v0 <= (signed_word) v1)
r = -((signed_word)v1 >= (signed_word) v0)
nleu/ngeu
r = -((unsigned_word) v0 <= (unsigned_word) v1)
r = -((unsigned_word) v1 >= (unsigned_word) v0)
nlts/ngts
r = -((signed_word) v0 < (signed_word) v1);
r = -((signed_word) v1 > (signed_word) v0)
nltu/ngtu
r = -((unsigned_word) v0 < (unsigned_word) v1)
r = -((unsigned_word) v1 > (unsigned_word) v0)
neq0
r = -(v0 == 0)
Table 5-3. Negative Comparisons and Negative Comparisons Against Zero
MPC7450 RISC Microprocessor Family Software Optimization Guide
Operation
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subf r5,r4,r3
addic r6,r5,-1
subfe r7,r7,r7
Cycles: 5
subf r5,r4,r3
subfic r6,r5,0
subfe r7,r7,r7
Cycles: 5
xoris r5,r3,0x8000
subf r6,r3,r4
addc r7,r6,r5
subfe r8,r8,r8
Cycles: 5
subfc r5,r3,r4
addze r6,r3
subf r7,r6,r3
Cycles: 5
subfc r5,r4,r3
srwi r6,r4,31
srwi r7,r3,31
subfe r8,r7,r6
Cycles: 4
subfc r5,r3,r3
subfe r6,r6,r6
Cycles: 4
addic r4,r3,-1
subfe r5,r5,r5
Cycles: 4
Compiler Writer’s
Guide Code
subf r5,r3,r4
subf r6,r4,r3
nor r7,r6,r5
srawi r8,r7,31
Cycles: 3
subf r5,r3,r4
subf r6,r4,r3
or r7,r6,r5
srawi r8,r7,31
Cycles: 3
cntlzw r4,r3
srwi r5,r4,5
neg r6,r5
Cycles: 3
MPC7450 Code
(If Different)
The MPC7450
sequence takes 4
cycles to complete, but
the GPR result in r8 is
available after 3 cycles.
As this is the only part
of the result that is
used, the sequence is
assumed to take 3
cycles.
The MPC7450
sequence takes 4
cycles to complete, but
the GPR result in r8 is
available after 3 cycles.
As this is the only part
of the result that is
used, the sequence is
assumed to take 3
cycles.
Comments
MOTOROLA