implemented conio peek functions for PCE target

libsrc/pce/cpeekc.s

@@ -0,0 +1,24 @@
+;
+; 2020-07-14, Groepaz
+;
+; char cpeekc (void);
+;
+; get character from current position, do NOT advance cursor
+
+        .export         _cpeekc
+
+        .include        "pce.inc"
+        .include        "extzp.inc"
+
+_cpeekc:
+        st0     #VDC_MARR       ; Memory-Address Read
+        ldy     SCREEN_PTR
+        ldx     SCREEN_PTR+1
+        sty     VDC_DATA_LO
+        stx     VDC_DATA_HI
+
+        st0     #VDC_VRR        ; VRAM Read Register
+        lda     VDC_DATA_LO     ; character
+        and     #<~$80          ; remove reverse bit
+        ldx     #0
+        rts

libsrc/pce/cpeekcolor.s

@@ -0,0 +1,28 @@
+;
+; 2020-07-14, Groepaz
+;
+; unsigned char cpeekcolor (void);
+;
+; get color from current position, do NOT advance cursor
+
+        .export         _cpeekcolor
+
+        .include        "pce.inc"
+        .include        "extzp.inc"
+
+_cpeekcolor:
+        st0     #VDC_MARR       ; Memory-Address Read
+        ldy     SCREEN_PTR
+        ldx     SCREEN_PTR+1
+        sty     VDC_DATA_LO
+        stx     VDC_DATA_HI
+
+        st0     #VDC_VRR        ; VRAM Read Register
+        lda     VDC_DATA_HI
+        and     #<~$02
+        lsr     a
+        lsr     a
+        lsr     a
+        lsr     a
+        ldx     #0
+        rts

libsrc/pce/cpeekrevers.s

@@ -0,0 +1,26 @@
+;
+; 2020-07-14, Groepaz
+;
+; unsigned char cpeekrevers (void);
+;
+; get inverse flag from current position, do NOT advance cursor
+
+        .export         _cpeekrevers
+
+        .include        "pce.inc"
+        .include        "extzp.inc"
+
+_cpeekrevers:
+        st0     #VDC_MARR       ; Memory-Address Read
+        ldy     SCREEN_PTR
+        ldx     SCREEN_PTR+1
+        sty     VDC_DATA_LO
+        stx     VDC_DATA_HI
+
+        st0     #VDC_VRR        ; VRAM Read Register
+        lda     VDC_DATA_LO     ; character (bit 7 is revers bit)
+        rol     a
+        rol     a
+        and     #1
+        ldx     #0
+        rts

libsrc/pce/cpeeks.s

@@ -0,0 +1,63 @@
+;
+; 2020-07-14, Groepaz
+;
+; void cpeeks (char* s, unsigned length);
+;
+; get string from current position, do NOT advance cursor
+
+        .export         _cpeeks
+
+        .import         popax
+        .importzp       ptr1, ptr2, tmp1, tmp2
+
+        .macpack        generic
+
+        .include        "pce.inc"
+        .include        "extzp.inc"
+
+_cpeeks:
+        eor     #<$FFFF         ; counting a word upward is faster
+        sta     ptr2            ; so, we use -(length + 1)
+        txa
+        eor     #>$FFFF
+        sta     ptr2+1
+
+        st0     #VDC_MARR       ; Memory-Address Read
+        ldy     SCREEN_PTR
+        ldx     SCREEN_PTR+1
+        sty     VDC_DATA_LO
+        stx     VDC_DATA_HI
+
+        st0     #VDC_VRR        ; VRAM Read Register
+
+        jsr     popax
+        sta     tmp1            ; (will be a .Y index)
+        stx     ptr1+1
+
+        ldx     #<$0000
+        stx     ptr1
+        beq     L2              ; branch always
+
+L3:     ldy     tmp2
+        lda     VDC_DATA_LO     ; get character
+        bit     VDC_DATA_HI     ; we need to "read" the highbyte to advance the address
+        iny
+        sty     tmp2
+        and     #<~$80          ; remove reverse bit
+
+        ldy     tmp1
+        sta     (ptr1),y
+        iny
+        bne     L1
+        inc     ptr1+1
+L1:     sty     tmp1
+
+L2:     inc     ptr2            ; count length
+        bne     L3
+        inc     ptr2+1
+        bne     L3
+
+        txa                     ; terminate the string
+        ldy     tmp1
+        sta     (ptr1),y
+        rts

libsrc/pce/cputc.s

@@ -68,10 +68,10 @@ putchar:
         sty     VDC_DATA_LO
         stx     VDC_DATA_HI
 
-        st0     #VDC_VWR
+        st0     #VDC_VWR        ; VRAM Write Register
         sta     VDC_DATA_LO     ; character
 
-        lda     CHARCOLOR       ; pallette number
+        lda     CHARCOLOR       ; palette number
         asl     a
         asl     a
         asl     a