mirror of https://github.com/cc65/cc65.git
54 lines
1.4 KiB
ArmAsm
54 lines
1.4 KiB
ArmAsm
;
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; Wayne Parham (wayne@parhamdata.com)
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; int __fastcall__ read (int fd, void* buf, unsigned count);
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;
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.include "sym1.inc"
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.import popax, popptr1
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.importzp ptr1, ptr2, ptr3
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.export _read
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.proc _read
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sta ptr3
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stx ptr3+1 ; Count in ptr3
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inx
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stx ptr2+1 ; Increment and store in ptr2
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tax
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inx
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stx ptr2
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jsr popptr1 ; Buffer address in ptr1
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jsr popax
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begin: dec ptr2
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bne getch
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dec ptr2+1
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beq done ; If buffer full, return
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getch: jsr INTCHR ; Get character using Monitor ROM call
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jsr OUTCHR ; Echo it
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and #$7F ; Clear top bit
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cmp #$07 ; Check for '\a'
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bne chkcr ; ...if BEL character
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jsr BEEP ; Make beep sound
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chkcr: cmp #$0D ; Check for '\r'
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bne putch ; ...if CR character
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lda #$0A ; Replace with '\n'
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jsr OUTCHR ; and echo it
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putch: ldy #$00 ; Put char into return buffer
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sta (ptr1),y
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inc ptr1 ; Increment pointer
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bne begin
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inc ptr1+1
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bne begin
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done: lda ptr3
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ldx ptr3+1
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rts ; Return count
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.endproc
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