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ack/mach/m68020/libem/dvu8.s

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Add 8-byte long long for linux68k. Add rules for 8-byte integers to m68020 ncg. Add 8-byte long long to ACK C on linux68k. Enable long-long tests for linux68k. The tests pass in our emulator using musahi; I don't have a real 68k processor and haven't tried other emulators. Still missing are conversions between 8-byte integers and any size of floats. The long-long tests don't cover these conversions, and our emulator can't do floating-point. Our build always enables TBL68020 and uses word size 4. Without TBL68020, 8-byte multiply and divide are missing. With word size 2, some conversions between 2-byte and 8-byte integers are missing. Fix .cii in libem, which didn't work when converting from 1-byte or 2-byte integers. Now .cii and .cuu work, but also add some rules to skip .cii and .cuu when converting 8-byte integers. The new rule for loc 4 loc 8 cii `with test_set4` exposes a bug: the table may believe that the condition codes test a 4-byte register when they only test a word or byte, and this incorrect test may describe an unsigned word or byte as negative. Another rule `with exact test_set1+test_set2` works around the bug by ignoring the negative flag, because a zero-extended word or byte is never negative. The old rules for comparison and logic do work with 8-byte integers and bitsets, but add some specific 8-byte rules to skip libem calls or loops. There were no rules for 8-byte arithmetic, shift, or rotate; so add some. There is a register shortage, because the table requires preserving d3 to d7, leaving only 3 data registers (d0, d1, d2) for 8-byte operations. Because of the shortage, the code may move data to an address register, or read a memory location more than once. The multiplication and division code are translations of the i386 code. They pass the tests, but might not give the best performance on a real 68k processor.
2019-09-24 17:32:17 +00:00
.define .dvu8
.sect .text
.sect .rom
.sect .data
.sect .bss
yh=8
xh=16
! .dvu8 yields d0:d1 = quotient from x / y
.sect .text
.dvu8:
move.l d3, -(sp) ! preserve caller's d3
move.l (xh, sp), d0
move.l (yh, sp), d1
sub.l #4, sp
jsr (.divrem8)
add.l #4, sp
move.l (sp)+, d3
rtd #16
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