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ed: allow appending at the end of the file
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@ -129,6 +129,8 @@ bufDelLines:
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; Insert string where DE points to memory scratchpad, then insert that line
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; at index HL, offsetting all lines by 2 bytes.
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bufInsertLine:
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call bufIndexInBounds
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jr nz, .append
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push de ; --> lvl 1, scratchpad ptr
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push hl ; --> lvl 2, insert index
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; The logic below is mostly copy-pasted from bufDelLines, but with a
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@ -155,6 +157,7 @@ bufInsertLine:
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inc de ; second byte beyond last line
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; HL = BUF_LINECNT-1, DE = BUF_LINECNT, BC is set. We're good!
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lddr
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.set:
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; We still need to increase BUF_LINECNT
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ld hl, (BUF_LINECNT)
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inc hl
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@ -168,6 +171,16 @@ bufInsertLine:
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inc hl
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ld (hl), d
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ret
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.append:
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; nothing to move, just put the line there. Let's piggy-back on the end
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; of the regular routine by carefully pushing the right register in the
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; right place.
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; But before that, make sure that HL isn't too high. The only place we
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; can append to is at (BUF_LINECNT)
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ld hl, (BUF_LINECNT)
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push de ; --> lvl 1
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push hl ; --> lvl 2
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jr .set
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; copy string that HL points to to scratchpad and return its pointer in
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; scratchpad, in HL.
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@ -181,3 +194,16 @@ bufScratchpadAdd:
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pop hl ; <-- lvl 1
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pop de
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ret
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; Sets Z according to whether the line index in HL is within bounds.
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bufIndexInBounds:
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push de
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ld de, (BUF_LINECNT)
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call cpHLDE
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pop de
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jr c, .withinBounds
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; out of bounds
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jp unsetZ
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.withinBounds:
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cp a ; ensure Z
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ret
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