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cc65/libsrc/runtime/asreax3.s
cuz d55c271c2a More shift routines
git-svn-id: svn://svn.cc65.org/cc65/trunk@820 b7a2c559-68d2-44c3-8de9-860c34a00d81
2001-07-25 21:36:01 +00:00

31 lines
548 B
ArmAsm

;
; Ullrich von Bassewitz, 06.08.1998
;
; CC65 runtime: Scale the 32 bit primary register by 8
;
.export asreax3
.importzp sreg, tmp1
asreax3:
stx tmp1
ldx sreg+1
cpx #$80 ; Get bit 7 into carry
ror sreg+1
ror sreg
ror tmp1
ror a
cpx #$80 ; Get bit 7 into carry
ror sreg+1
ror sreg
ror tmp1
ror a
cpx #$80 ; Get bit 7 into carry
ror sreg+1
ror sreg
ror tmp1
ror a
ldx tmp1
rts