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https://github.com/cc65/cc65.git
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53dd513176
which included commits to RCS files with non-trunk default branches. git-svn-id: svn://svn.cc65.org/cc65/trunk@3 b7a2c559-68d2-44c3-8de9-860c34a00d81
266 lines
3.4 KiB
ArmAsm
266 lines
3.4 KiB
ArmAsm
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; Runtime code for cc65.
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;
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.import ldai, ldaxi, pushax
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.importzp sp, tmp1, tmp2, tmp3, ptr1, ptr4
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; Pop a from stack
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.export popa
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popa: ldy #0
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lda (sp),y ; Read byte
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inc sp
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bne *+4
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inc sp+1
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rts
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;
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; pop a from stack and load x with zero
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;
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.export popa0
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popa0: ldy #0
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lda (sp),y ; load low byte
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ldx #0
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beq incsp2
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;
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; pop a/x from stack. This function will run directly into incsp2
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;
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.export popax ; pop stack into AX
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popax: ldy #1
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lda (sp),y ; get hi byte
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tax ; into x
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dey
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lda (sp),y ; get lo byte
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;
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; routines for inc/dec'ing sp
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;
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.export addysp, addysp1
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.export incsp1, incsp2, incsp3, incsp4
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.export incsp5, incsp6, incsp7, incsp8
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; do this by hand, cause it gets used a lot
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incsp2: ldy sp ; 3
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iny ; 2
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beq @L1 ; 2
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iny ; 2
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beq @L2 ; 2
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sty sp ; 3
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rts
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@L1: iny ; 2
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@L2: sty sp ; 3
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inc sp+1 ; 5
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rts
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; Hand optimize this one also...
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incsp1: inc sp
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bne *+4
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inc sp+1
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rts
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incsp3: ldy #3
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bne addysp
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incsp4: ldy #4
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bne addysp
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incsp5: ldy #5
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bne addysp
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incsp6: ldy #6
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bne addysp
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incsp7: ldy #7
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bne addysp
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incsp8: ldy #8
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bne addysp
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addysp1:
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iny
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addysp: pha ; save A
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clc
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tya ; get the value
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adc sp ; add lo byte
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sta sp ; put it back
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bcc addysp_1 ; if no carry, we're done
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inc sp+1 ; inc hi byte
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addysp_1:
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pla ; get A back
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rts
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;
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;
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.export subysp ; sub Y from SP
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.export decsp1, decsp2, decsp3, decsp4
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.export decsp5, decsp6, decsp7, decsp8
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; Do this one by hand, cause it gets used a lot
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decsp2: ldy sp
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beq @L1
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dey
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beq @L2
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dey
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sty sp
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rts
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@L1: dey
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@L2: dey
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sty sp
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dec sp+1
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rts
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; Decrement by 1 also done as fast as possible
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decsp1: ldy sp
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bne *+4
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dec sp+1
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dec sp
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rts
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decsp3: ldy #3
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bne subysp
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decsp4: ldy #4
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bne subysp
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decsp5: ldy #5
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bne subysp
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decsp6: ldy #6
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bne subysp
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decsp7: ldy #7
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bne subysp
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decsp8: ldy #8
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; bne subysp
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subysp: pha ; save A
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sty tmp1 ; save the value
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lda sp ; get lo byte
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sec
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sbc tmp1 ; sub y val
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sta sp ; put it back
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bcs *+4
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dec sp+1
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pla ; get A back
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rts ; done
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;
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; Various kinds of store operators
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;
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; store AX at SP@@(Y)
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.export staxspidx, staspidx, staspic
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staxspidx:
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jsr staspic ; use common part
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pha
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iny
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lda tmp2
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sta (ptr4),y
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tax
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pla
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rts
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staspidx:
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jsr staspic ; use common part
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ldx tmp2
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rts
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staspic:
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sta tmp1
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stx tmp2
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sty tmp3
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jsr popax ; get the pointer
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sta ptr4
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stx ptr4+1
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ldy tmp3
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lda tmp1
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sta (ptr4),y
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rts
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; ax --> (sp),y
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.export staxspp ; store AX thru (sp), and pop
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staxspp:
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ldy #0
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pha
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lda (sp),y
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sta ptr1
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iny
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lda (sp),y
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sta ptr1+1
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txa
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sta (ptr1),y
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pla
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dey
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sta (ptr1),y
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jmp incsp2 ; Drop address
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.export staspp ; store A thru (sp), and pop
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staspp:
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ldy #1
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pha
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lda (sp),y
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sta ptr1+1
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dey
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lda (sp),y
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sta ptr1
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pla
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sta (ptr1),y
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jmp incsp2 ; Drop address
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;
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; Boolean function return entries.
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;
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.export return0, return1
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return1:
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ldx #0
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lda #1
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rts
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return0:
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lda #0
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tax
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rts
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;
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; random stuff
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;
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; (a/x) 16--> (--sp)
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.export pushwaxi
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pushwaxi: ; push word at (ax)
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jsr ldaxi
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jmp pushax
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; (a/x) 8--> (--sp)
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.export pushbaxi ; push byte at (ax)
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pushbaxi:
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jsr ldai
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jmp pushax
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