Add KIM-1 Support

libsrc/kim1/read.s

@@ -0,0 +1,51 @@
+;
+; int __fastcall__ read (int fd, void* buf, unsigned count);
+;
+
+.include        "kim1.inc"
+
+.import         popax, popptr1
+.importzp       ptr1, ptr2, ptr3
+
+.export         _read
+
+.proc           _read
+
+        sta     ptr3
+        stx     ptr3+1           ; Count in ptr3
+        inx
+        stx     ptr2+1           ; Increment and store in ptr2
+        tax
+        inx
+        stx     ptr2
+        jsr     popptr1          ; Buffer address in ptr1
+        jsr     popax
+
+begin:  dec     ptr2
+        bne     getch
+        dec     ptr2+1
+        beq     done             ; If buffer full, return
+
+getch:  jsr     INTCHR           ; Get character using Monitor ROM call
+        ;jsr     OUTCHR           ; Echo it
+        and     #$7F             ; Clear top bit
+        cmp     #$07             ; Check for '\a'
+        bne     chkcr            ; ...if BEL character
+        ;jsr     BEEP             ; Make beep sound TODO
+chkcr:  cmp     #$0D             ; Check for '\r'
+        bne     putch            ; ...if CR character
+        lda     #$0A             ; Replace with '\n'
+        jsr     OUTCHR           ; and echo it
+
+putch:  ldy     #$00             ; Put char into return buffer
+        sta     (ptr1),y
+        inc     ptr1             ; Increment pointer
+        bne     begin
+        inc     ptr1+1
+        bne     begin
+
+done:   lda     ptr3
+        ldx     ptr3+1
+        rts                      ; Return count
+
+.endproc