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support packed word tables > $FF bytes long

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Paul Gardner-Stephen committed 2019-04-24 21:25:22 +09:30
1 parent 4bca352653
commit 9a0191d1e6
1 file changed
+32 -17
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c64/basic/print_packed_message.s
+32 -17
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@@ -54,43 +54,62 @@ print_packed_word:
;; A = the word to print ;; A = the word to print
tax tax
;; Setup pointer to packed words
lda #<packed_message_words
sta temp_string_ptr+0
lda #>packed_message_words
sta temp_string_ptr+1
;; Find the word in the list ;; Find the word in the list
ldy #$ff ldy #$ff
packed_word_search: packed_word_search:
cpx #$00 cpx #$00
beq found_packed_word beq found_packed_word
iny iny
lda packed_message_words,y lda (temp_string_ptr),y
and #$0f and #$0f
cmp #$00 cmp #$00
bne + bne +
dex dex
* *
;; Advance to next page if required
cpy #$ff cpy #$ff
bne packed_word_search bne packed_word_search
;; Could not find word inc temp_string_ptr+1
sec jmp packed_word_search
rts
found_packed_word: found_packed_word:
;; Get pointer to start of packed word
;; Make sure we don't wrap on a page boundary
tya
clc
adc temp_string_ptr+0
sta temp_string_ptr+0
lda temp_string_ptr+1
adc #$00
sta temp_string_ptr+1
ldy #$00
next_packed_word_char:
;; Y = offset into packed word data - 1 ;; Y = offset into packed word data - 1
iny iny
;; Check for end of word ;; Check for end of word
lda packed_message_words,y lda (temp_string_ptr),y
cmp #$00 cmp #$00
beq done_printing_word beq end_of_packed_word
and #$f0 and #$f0
beq done_printing_word beq end_of_packed_word
;; Check if it is an uncommon char ;; Check if it is an uncommon char
lda packed_message_words,y lda (temp_string_ptr),y
and #$f0 and #$f0
cmp #$f0 cmp #$f0
beq is_uncommon_char beq is_uncommon_char
;; Is not an uncommon char, so get char of upper nybl ;; Is not an uncommon char, so get char of upper nybl
lda packed_message_words,y lda (temp_string_ptr),y
;; Put high nybl into low bits of X ;; Put high nybl into low bits of X
lsr lsr
@@ -110,7 +129,7 @@ found_packed_word:
;; See if there is a char in the low nybl to print ;; See if there is a char in the low nybl to print
pla pla
tay tay
lda packed_message_words,y lda (temp_string_ptr),y
and #$0f and #$0f
beq end_of_packed_word beq end_of_packed_word
cmp #$0f cmp #$0f
@@ -141,7 +160,7 @@ has_nybl:
no_lo_nybl_char: no_lo_nybl_char:
cpy #$ff cpy #$ff
bne found_packed_word bne next_packed_word_char
end_of_packed_word: end_of_packed_word:
;; Hit end of packed data ;; Hit end of packed data
rts rts
@@ -149,7 +168,7 @@ end_of_packed_word:
is_uncommon_char: is_uncommon_char:
;; Lower nybl has offset into low-frequency part of the table ;; Lower nybl has offset into low-frequency part of the table
lda packed_message_words,y lda (temp_string_ptr),y
and #$0f and #$0f
clc clc
adc #14 adc #14
@@ -160,7 +179,3 @@ is_uncommon_char:
pha pha
jmp has_nybl jmp has_nybl
done_printing_word:
rts