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ack/mach/powerpc/libem/fef8.s

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In PowerPC libem, use the new features of our assembler. The new features are the hi16/lo16 and ha16/lo16 syntax for relocations, and the extended mnemonics like "blr". Use ha16/lo16 to load some double floats with 2 instructions (lis/lfd) instead of 3 (lis/ori/lfd). Use the extended names for branches, comparisons, and bit rotations, so I can more easily read the code. The new names often encode the same machine instructions as the old names, except in a few places where I changed the instructions. Stop using andi. when we don't need to set cr0. In inn.s, I change andi. to extrwi to extract the same bits. In los.s and sts.s, I change "andi. r3, r3, ~3" to "clrrwi r3, r3, 2". This avoids setting cr0 and also stops clearing the high 16 bits of r3. In csa.s, los.s, sts.s, I change some comparisons and right shifts from signed to unsigned (cmplw, cmplwi, srwi), because the sizes are unsigned. In inn.s, the right shift can be signed (sraw) or unsigned (srw), but I use srw because we don't need the carry bit. In fef8.s, I save an instruction by using rlwinm instead of addis/andc to rlwinm to clear a field. The code no longer kills r7. In both fef8.s and fif8.s, I remove the list of killed registers. Also remove some whitespace from ends of lines.
2017-01-23 22:16:39 +00:00
.sect .text; .sect .rom; .sect .data; .sect .bss
Rewrite fef 8 in powerpc assembly. In EM, fef splits a float into exponent and fraction. The old C code, given an infinite float, got stuck in an infinite loop. The new assembly code doesn't loop; it extracts the IEEE exponent.
2016-09-29 19:52:54 +00:00
.sect .text
! Split a double-precision float into fraction and exponent, like
! frexp(3) in C. On entry:
! r3 = float, high word (bits 0..31)
! r4 = float, low word (bits 32..63)
! Yields:
! r3 = fraction, high word (bits 0..31)
! r4 = fraction, low word (bits 32..63)
! r5 = exponent
.define .fef8
.fef8:
! IEEE double-precision format:
! sign exponent fraction
! 0 1..11 12..63
In PowerPC libem, use the new features of our assembler. The new features are the hi16/lo16 and ha16/lo16 syntax for relocations, and the extended mnemonics like "blr". Use ha16/lo16 to load some double floats with 2 instructions (lis/lfd) instead of 3 (lis/ori/lfd). Use the extended names for branches, comparisons, and bit rotations, so I can more easily read the code. The new names often encode the same machine instructions as the old names, except in a few places where I changed the instructions. Stop using andi. when we don't need to set cr0. In inn.s, I change andi. to extrwi to extract the same bits. In los.s and sts.s, I change "andi. r3, r3, ~3" to "clrrwi r3, r3, 2". This avoids setting cr0 and also stops clearing the high 16 bits of r3. In csa.s, los.s, sts.s, I change some comparisons and right shifts from signed to unsigned (cmplw, cmplwi, srwi), because the sizes are unsigned. In inn.s, the right shift can be signed (sraw) or unsigned (srw), but I use srw because we don't need the carry bit. In fef8.s, I save an instruction by using rlwinm instead of addis/andc to rlwinm to clear a field. The code no longer kills r7. In both fef8.s and fif8.s, I remove the list of killed registers. Also remove some whitespace from ends of lines.
2017-01-23 22:16:39 +00:00
extrwi r6, r3, 11, 1 ! r6 = IEEE exponent
Rewrite fef 8 in powerpc assembly. In EM, fef splits a float into exponent and fraction. The old C code, given an infinite float, got stuck in an infinite loop. The new assembly code doesn't loop; it extracts the IEEE exponent.
2016-09-29 19:52:54 +00:00
addi r5, r6, -1022 ! r5 = true exponent
In PowerPC libem, use the new features of our assembler. The new features are the hi16/lo16 and ha16/lo16 syntax for relocations, and the extended mnemonics like "blr". Use ha16/lo16 to load some double floats with 2 instructions (lis/lfd) instead of 3 (lis/ori/lfd). Use the extended names for branches, comparisons, and bit rotations, so I can more easily read the code. The new names often encode the same machine instructions as the old names, except in a few places where I changed the instructions. Stop using andi. when we don't need to set cr0. In inn.s, I change andi. to extrwi to extract the same bits. In los.s and sts.s, I change "andi. r3, r3, ~3" to "clrrwi r3, r3, 2". This avoids setting cr0 and also stops clearing the high 16 bits of r3. In csa.s, los.s, sts.s, I change some comparisons and right shifts from signed to unsigned (cmplw, cmplwi, srwi), because the sizes are unsigned. In inn.s, the right shift can be signed (sraw) or unsigned (srw), but I use srw because we don't need the carry bit. In fef8.s, I save an instruction by using rlwinm instead of addis/andc to rlwinm to clear a field. The code no longer kills r7. In both fef8.s and fif8.s, I remove the list of killed registers. Also remove some whitespace from ends of lines.
2017-01-23 22:16:39 +00:00
cmpwi r6, 2047
beqlr ! return if infinity or NaN
cmpwi r6, 0
bne 1f ! jump if normalized number
Rewrite fef 8 in powerpc assembly. In EM, fef splits a float into exponent and fraction. The old C code, given an infinite float, got stuck in an infinite loop. The new assembly code doesn't loop; it extracts the IEEE exponent.
2016-09-29 19:52:54 +00:00
! Got denormalized number or zero, probably zero.
In PowerPC libem, use the new features of our assembler. The new features are the hi16/lo16 and ha16/lo16 syntax for relocations, and the extended mnemonics like "blr". Use ha16/lo16 to load some double floats with 2 instructions (lis/lfd) instead of 3 (lis/ori/lfd). Use the extended names for branches, comparisons, and bit rotations, so I can more easily read the code. The new names often encode the same machine instructions as the old names, except in a few places where I changed the instructions. Stop using andi. when we don't need to set cr0. In inn.s, I change andi. to extrwi to extract the same bits. In los.s and sts.s, I change "andi. r3, r3, ~3" to "clrrwi r3, r3, 2". This avoids setting cr0 and also stops clearing the high 16 bits of r3. In csa.s, los.s, sts.s, I change some comparisons and right shifts from signed to unsigned (cmplw, cmplwi, srwi), because the sizes are unsigned. In inn.s, the right shift can be signed (sraw) or unsigned (srw), but I use srw because we don't need the carry bit. In fef8.s, I save an instruction by using rlwinm instead of addis/andc to rlwinm to clear a field. The code no longer kills r7. In both fef8.s and fif8.s, I remove the list of killed registers. Also remove some whitespace from ends of lines.
2017-01-23 22:16:39 +00:00
extrwi r6, r3, 22, 12
Rewrite fef 8 in powerpc assembly. In EM, fef splits a float into exponent and fraction. The old C code, given an infinite float, got stuck in an infinite loop. The new assembly code doesn't loop; it extracts the IEEE exponent.
2016-09-29 19:52:54 +00:00
addi r5, r0, 0 ! r5 = true exponent = 0
or. r6, r6, r4 ! r6 = high|low fraction
In PowerPC libem, use the new features of our assembler. The new features are the hi16/lo16 and ha16/lo16 syntax for relocations, and the extended mnemonics like "blr". Use ha16/lo16 to load some double floats with 2 instructions (lis/lfd) instead of 3 (lis/ori/lfd). Use the extended names for branches, comparisons, and bit rotations, so I can more easily read the code. The new names often encode the same machine instructions as the old names, except in a few places where I changed the instructions. Stop using andi. when we don't need to set cr0. In inn.s, I change andi. to extrwi to extract the same bits. In los.s and sts.s, I change "andi. r3, r3, ~3" to "clrrwi r3, r3, 2". This avoids setting cr0 and also stops clearing the high 16 bits of r3. In csa.s, los.s, sts.s, I change some comparisons and right shifts from signed to unsigned (cmplw, cmplwi, srwi), because the sizes are unsigned. In inn.s, the right shift can be signed (sraw) or unsigned (srw), but I use srw because we don't need the carry bit. In fef8.s, I save an instruction by using rlwinm instead of addis/andc to rlwinm to clear a field. The code no longer kills r7. In both fef8.s and fif8.s, I remove the list of killed registers. Also remove some whitespace from ends of lines.
2017-01-23 22:16:39 +00:00
beqlr ! return if zero
Rewrite fef 8 in powerpc assembly. In EM, fef splits a float into exponent and fraction. The old C code, given an infinite float, got stuck in an infinite loop. The new assembly code doesn't loop; it extracts the IEEE exponent.
2016-09-29 19:52:54 +00:00
! Got denormalized number, not zero.
stwu r4, -4(sp)
stwu r3, -4(sp)
lfd f0, 0(sp)
In PowerPC libem, use the new features of our assembler. The new features are the hi16/lo16 and ha16/lo16 syntax for relocations, and the extended mnemonics like "blr". Use ha16/lo16 to load some double floats with 2 instructions (lis/lfd) instead of 3 (lis/ori/lfd). Use the extended names for branches, comparisons, and bit rotations, so I can more easily read the code. The new names often encode the same machine instructions as the old names, except in a few places where I changed the instructions. Stop using andi. when we don't need to set cr0. In inn.s, I change andi. to extrwi to extract the same bits. In los.s and sts.s, I change "andi. r3, r3, ~3" to "clrrwi r3, r3, 2". This avoids setting cr0 and also stops clearing the high 16 bits of r3. In csa.s, los.s, sts.s, I change some comparisons and right shifts from signed to unsigned (cmplw, cmplwi, srwi), because the sizes are unsigned. In inn.s, the right shift can be signed (sraw) or unsigned (srw), but I use srw because we don't need the carry bit. In fef8.s, I save an instruction by using rlwinm instead of addis/andc to rlwinm to clear a field. The code no longer kills r7. In both fef8.s and fif8.s, I remove the list of killed registers. Also remove some whitespace from ends of lines.
2017-01-23 22:16:39 +00:00
lis r6, ha16[_2_64]
lfd f1, lo16[_2_64](r6)
Rewrite fef 8 in powerpc assembly. In EM, fef splits a float into exponent and fraction. The old C code, given an infinite float, got stuck in an infinite loop. The new assembly code doesn't loop; it extracts the IEEE exponent.
2016-09-29 19:52:54 +00:00
fmul f0, f0, f1 ! multiply it by 2**64
stfd f0, 0(sp)
lwz r3, 0(sp)
lwz r4, 4(sp)
In PowerPC libem, use the new features of our assembler. The new features are the hi16/lo16 and ha16/lo16 syntax for relocations, and the extended mnemonics like "blr". Use ha16/lo16 to load some double floats with 2 instructions (lis/lfd) instead of 3 (lis/ori/lfd). Use the extended names for branches, comparisons, and bit rotations, so I can more easily read the code. The new names often encode the same machine instructions as the old names, except in a few places where I changed the instructions. Stop using andi. when we don't need to set cr0. In inn.s, I change andi. to extrwi to extract the same bits. In los.s and sts.s, I change "andi. r3, r3, ~3" to "clrrwi r3, r3, 2". This avoids setting cr0 and also stops clearing the high 16 bits of r3. In csa.s, los.s, sts.s, I change some comparisons and right shifts from signed to unsigned (cmplw, cmplwi, srwi), because the sizes are unsigned. In inn.s, the right shift can be signed (sraw) or unsigned (srw), but I use srw because we don't need the carry bit. In fef8.s, I save an instruction by using rlwinm instead of addis/andc to rlwinm to clear a field. The code no longer kills r7. In both fef8.s and fif8.s, I remove the list of killed registers. Also remove some whitespace from ends of lines.
2017-01-23 22:16:39 +00:00
extrwi r6, r3, 11, 1 ! r6 = IEEE exponent
Rewrite fef 8 in powerpc assembly. In EM, fef splits a float into exponent and fraction. The old C code, given an infinite float, got stuck in an infinite loop. The new assembly code doesn't loop; it extracts the IEEE exponent.
2016-09-29 19:52:54 +00:00
addi sp, sp, 8
addi r5, r6, -1022 - 64 ! r5 = true exponent
1:
! Put fraction in [0.5, 1) or (-1, -0.5] by setting its
! exponent to true 0, IEEE 1022.
In PowerPC libem, use the new features of our assembler. The new features are the hi16/lo16 and ha16/lo16 syntax for relocations, and the extended mnemonics like "blr". Use ha16/lo16 to load some double floats with 2 instructions (lis/lfd) instead of 3 (lis/ori/lfd). Use the extended names for branches, comparisons, and bit rotations, so I can more easily read the code. The new names often encode the same machine instructions as the old names, except in a few places where I changed the instructions. Stop using andi. when we don't need to set cr0. In inn.s, I change andi. to extrwi to extract the same bits. In los.s and sts.s, I change "andi. r3, r3, ~3" to "clrrwi r3, r3, 2". This avoids setting cr0 and also stops clearing the high 16 bits of r3. In csa.s, los.s, sts.s, I change some comparisons and right shifts from signed to unsigned (cmplw, cmplwi, srwi), because the sizes are unsigned. In inn.s, the right shift can be signed (sraw) or unsigned (srw), but I use srw because we don't need the carry bit. In fef8.s, I save an instruction by using rlwinm instead of addis/andc to rlwinm to clear a field. The code no longer kills r7. In both fef8.s and fif8.s, I remove the list of killed registers. Also remove some whitespace from ends of lines.
2017-01-23 22:16:39 +00:00
rlwinm r3, r3, 0, 12, 0 ! clear old exponent
Rewrite fef 8 in powerpc assembly. In EM, fef splits a float into exponent and fraction. The old C code, given an infinite float, got stuck in an infinite loop. The new assembly code doesn't loop; it extracts the IEEE exponent.
2016-09-29 19:52:54 +00:00
oris r3, r3, 1022 << 4 ! set new exponent
In PowerPC libem, use the new features of our assembler. The new features are the hi16/lo16 and ha16/lo16 syntax for relocations, and the extended mnemonics like "blr". Use ha16/lo16 to load some double floats with 2 instructions (lis/lfd) instead of 3 (lis/ori/lfd). Use the extended names for branches, comparisons, and bit rotations, so I can more easily read the code. The new names often encode the same machine instructions as the old names, except in a few places where I changed the instructions. Stop using andi. when we don't need to set cr0. In inn.s, I change andi. to extrwi to extract the same bits. In los.s and sts.s, I change "andi. r3, r3, ~3" to "clrrwi r3, r3, 2". This avoids setting cr0 and also stops clearing the high 16 bits of r3. In csa.s, los.s, sts.s, I change some comparisons and right shifts from signed to unsigned (cmplw, cmplwi, srwi), because the sizes are unsigned. In inn.s, the right shift can be signed (sraw) or unsigned (srw), but I use srw because we don't need the carry bit. In fef8.s, I save an instruction by using rlwinm instead of addis/andc to rlwinm to clear a field. The code no longer kills r7. In both fef8.s and fif8.s, I remove the list of killed registers. Also remove some whitespace from ends of lines.
2017-01-23 22:16:39 +00:00
blr
Rewrite fef 8 in powerpc assembly. In EM, fef splits a float into exponent and fraction. The old C code, given an infinite float, got stuck in an infinite loop. The new assembly code doesn't loop; it extracts the IEEE exponent.
2016-09-29 19:52:54 +00:00
.sect .rom
_2_64:
! (double) 2**64
.data4 0x43f00000
.data4 0x00000000
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