d0p1/ack
1
0
Fork 0
Code Issues Pull requests Packages Projects Releases Wiki Activity
ack/mach/powerpc/libem/fef8.s

64 lines
1.5 KiB
ArmAsm
Raw Normal View History

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
Change .fef8 and .fif8 to pass values on the stack. Reorder the code in .fef8 and .fif8 so that in the usual case, we fall through to the blr without taking any branches. The usual case, by my guess, is .fef8 with normalized numbers or .fif8 with small integers. I change .fef8 and .fif8 to pass values on the real stack, not in specific registers. This simplifies the ncg table, and might help me experiment with changes to the ncg table. This change might or might not help mcg. Seems that mcg always uses the stack to pass values to libem, but I have not tested .fef8 or .fif8 with mcg.
2017-02-12 21:44:37 +00:00
! frexp(3) in C.
!
! Stack: ( double -- fraction 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
.define .fef8
.fef8:
Change .fef8 and .fif8 to pass values on the stack. Reorder the code in .fef8 and .fif8 so that in the usual case, we fall through to the blr without taking any branches. The usual case, by my guess, is .fef8 with normalized numbers or .fif8 with small integers. I change .fef8 and .fif8 to pass values on the real stack, not in specific registers. This simplifies the ncg table, and might help me experiment with changes to the ncg table. This change might or might not help mcg. Seems that mcg always uses the stack to pass values to libem, but I have not tested .fef8 or .fif8 with mcg.
2017-02-12 21:44:37 +00:00
lwz r3, 0(sp) ! r3 = high word (bits 0..31)
lwz r4, 4(sp) ! r4 = low word (bits 32..63)
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
! IEEE double-precision format:
! sign exponent fraction
! 0 1..11 12..63
Change .fef8 and .fif8 to pass values on the stack. Reorder the code in .fef8 and .fif8 so that in the usual case, we fall through to the blr without taking any branches. The usual case, by my guess, is .fef8 with normalized numbers or .fif8 with small integers. I change .fef8 and .fif8 to pass values on the real stack, not in specific registers. This simplifies the ncg table, and might help me experiment with changes to the ncg table. This change might or might not help mcg. Seems that mcg always uses the stack to pass values to libem, but I have not tested .fef8 or .fif8 with mcg.
2017-02-12 21:44:37 +00:00
!
! To get fraction in [0.5, 1) or (-1, -0.5], we subtract 1022
! from the IEEE exponent.
extrwi. r6, r3, 11, 1 ! r6 = IEEE exponent
addi r5, r6, -1022 ! r5 = our exponent
beq 2f ! jump if zero or denormalized
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
Change .fef8 and .fif8 to pass values on the stack. Reorder the code in .fef8 and .fif8 so that in the usual case, we fall through to the blr without taking any branches. The usual case, by my guess, is .fef8 with normalized numbers or .fif8 with small integers. I change .fef8 and .fif8 to pass values on the real stack, not in specific registers. This simplifies the ncg table, and might help me experiment with changes to the ncg table. This change might or might not help mcg. Seems that mcg always uses the stack to pass values to libem, but I have not tested .fef8 or .fif8 with mcg.
2017-02-12 21:44:37 +00:00
beq 1f ! jump if infinity or NaN
! fall through if normalized
! Put fraction in [0.5, 1) or (-1, -0.5] by setting its
! IEEE exponent to 1022.
rlwinm r3, r3, 0, 12, 0 ! clear old exponent
oris r3, r3, 1022 << 4 ! set new exponent
! fall through
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
Change .fef8 and .fif8 to pass values on the stack. Reorder the code in .fef8 and .fif8 so that in the usual case, we fall through to the blr without taking any branches. The usual case, by my guess, is .fef8 with normalized numbers or .fif8 with small integers. I change .fef8 and .fif8 to pass values on the real stack, not in specific registers. This simplifies the ncg table, and might help me experiment with changes to the ncg table. This change might or might not help mcg. Seems that mcg always uses the stack to pass values to libem, but I have not tested .fef8 or .fif8 with mcg.
2017-02-12 21:44:37 +00:00
1: stw r3, 0(sp)
stw r4, 4(sp) ! push fraction
stwu r5, -4(sp) ! push exponent
blr
2: ! 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
or. r6, r6, r4 ! r6 = high|low fraction
Change .fef8 and .fif8 to pass values on the stack. Reorder the code in .fef8 and .fif8 so that in the usual case, we fall through to the blr without taking any branches. The usual case, by my guess, is .fef8 with normalized numbers or .fif8 with small integers. I change .fef8 and .fif8 to pass values on the real stack, not in specific registers. This simplifies the ncg table, and might help me experiment with changes to the ncg table. This change might or might not help mcg. Seems that mcg always uses the stack to pass values to libem, but I have not tested .fef8 or .fif8 with mcg.
2017-02-12 21:44:37 +00:00
bne 3f ! jump if not zero
li r5, 0 ! exponent = 0
b 1b
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
Change .fef8 and .fif8 to pass values on the stack. Reorder the code in .fef8 and .fif8 so that in the usual case, we fall through to the blr without taking any branches. The usual case, by my guess, is .fef8 with normalized numbers or .fif8 with small integers. I change .fef8 and .fif8 to pass values on the real stack, not in specific registers. This simplifies the ncg table, and might help me experiment with changes to the ncg table. This change might or might not help mcg. Seems that mcg always uses the stack to pass values to libem, but I have not tested .fef8 or .fif8 with mcg.
2017-02-12 21:44:37 +00:00
3: ! Got denormalized number, not 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
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
Change .fef8 and .fif8 to pass values on the stack. Reorder the code in .fef8 and .fif8 so that in the usual case, we fall through to the blr without taking any branches. The usual case, by my guess, is .fef8 with normalized numbers or .fif8 with small integers. I change .fef8 and .fif8 to pass values on the real stack, not in specific registers. This simplifies the ncg table, and might help me experiment with changes to the ncg table. This change might or might not help mcg. Seems that mcg always uses the stack to pass values to libem, but I have not tested .fef8 or .fif8 with mcg.
2017-02-12 21:44:37 +00:00
addi r5, r6, -1022 - 64 ! r5 = our exponent
b 1b
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
Reference in a new issue Copy permalink