On Wed, 2020-01-22 at 10:14 +0200, Claudiu Zissulescu wrote: > ARC600 when configured with mul64 instructions uses mlo and mhi > registers to store the 64 result of the multiplication. In the ARC600 > ISA documentation we have the next register configuration when ARC600 > is configured only with mul64 extension: > > Register | Name | Use > ---------+------+------------------------------------ > r57 | mlo | Multiply low 32 bits, read only > r58 | mmid | Multiply middle 32 bits, read only > r59 | mhi | Multiply high 32 bits, read only > ----------------------------------------------------- > > When used for Co-existence configurations we have for mul64 the next > registers used: > > Register | Name | Use > ---------+------+------------------------------------ > r58 | mlo | Multiply low 32 bits, read only > r59 | mhi | Multiply high 32 bits, read only > ----------------------------------------------------- > > Note that mlo/mhi assignment doesn't swap when bigendian CPU > configuration is used. > > The compiler will always use r58 for mlo, regardless of the > configuration choosen to ensure mlo/mhi correct splitting. Fixing mlo > to the right register number is done at assembly time. The dwarf info > is also notified via DBX_... macro. Both mlo/mhi registers needs to > saved when ISR happens using a custom sequence. > > gcc/ > xxxx-xx-xx Claudiu Zissulescu <claz...@synopsys.com> > > * config/arc/arc-protos.h (gen_mlo): Remove. > (gen_mhi): Likewise. > * config/arc/arc.c (AUX_MULHI): Define. > (arc_must_save_reister): Special handling for r58/59. > (arc_compute_frame_size): Consider mlo/mhi registers. > (arc_save_callee_saves): Emit fp/sp move only when emit_move > paramter is true. > (arc_conditional_register_usage): Remove TARGET_BIG_ENDIAN from > mlo/mhi name selection. > (arc_restore_callee_saves): Don't early restore blink when ISR. > (arc_expand_prologue): Add mlo/mhi saving. > (arc_expand_epilogue): Add mlo/mhi restoring. > (gen_mlo): Remove. > (gen_mhi): Remove. > * config/arc/arc.h (DBX_REGISTER_NUMBER): Correct register > numbering when MUL64 option is used. > (DWARF2_FRAME_REG_OUT): Define. > * config/arc/arc.md (arc600_stall): New pattern. > (VUNSPEC_ARC_ARC600_STALL): Define. > (mulsi64): Use correct mlo/mhi registers. > (mulsi_600): Clean it up. > * config/arc/predicates.md (mlo_operand): Remove any dependency on > TARGET_BIG_ENDIAN. > (mhi_operand): Likewise. > > testsuite/ > xxxx-xx-xx Claudiu Zissulescu <claz...@synopsys.com> > * gcc.target/arc/code-density-flag.c: Update test. > * gcc.target/arc/interrupt-6.c: Likewise. Ugh. But OK.
jeff >
