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EDIT: Implemented faster version of memmove() in descending direction

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Bobbi Webber-Manners 2020-08-26 19:40:12 -04:00
parent 5d772344c7
commit f810a64ead
1 changed files with 35 additions and 25 deletions
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60
apps/edit.c
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@ -150,7 +150,7 @@ void set_gapbuf(uint16_t i, char c) {
* Must be in LC
* dst - Destination index into gapbuf[]
* src - Source index into gapbuf[]
* n - Length in bytes
* n - Length in bytes
*/
#pragma code-name (push, "LC")
void move_in_gapbuf(uint16_t dst, uint16_t src, size_t n) {
@ -158,39 +158,49 @@ void move_in_gapbuf(uint16_t dst, uint16_t src, size_t n) {
if (dst > src) {
// Start with highest addr and copy downwards
*(uint16_t*)(0xfa) = n; // Stuff sz in ZP
*(uint16_t*)(0xfc) = (uint16_t)0x0800 + src + n - 1; // Stuff src in ZP
*(uint16_t*)(0xfe) = (uint16_t)0x0800 + dst + n - 1; // Stuff dst in ZP
*(uint16_t*)(0xfc) = (uint16_t)0x0800 + src - 1; // Stuff src in ZP
*(uint16_t*)(0xfe) = (uint16_t)0x0800 + dst - 1; // Stuff dst in ZP
#ifdef AUXMEM
__asm__("lda %v", auxbank);
__asm__("sta $c073"); // Set aux bank
__asm__("sta $c005"); // Write aux mem
__asm__("sta $c003"); // Read aux mem
#endif
__asm__("clc"); // Prepare the source pointer
__asm__("lda $fd"); // MSB of source
__asm__("adc $fb"); // MSB of n
__asm__("sta $fd");
__asm__("clc"); // Prepare the dest pointer
__asm__("lda $ff"); // MSB of dest
__asm__("adc $fb"); // MSB of n
__asm__("sta $ff");
__asm__("ldy $fa"); // LSB of n
dl1:
__asm__("lda ($fc)"); // *src
__asm__("sta ($fe)"); // -> *dst
__asm__("lda $fc"); // LSB of src
__asm__("bne %g", ds1);
__asm__("dec $fd"); // MSB of src
__asm__("cpy #$00"); // Copy leftover bytes
__asm__("beq %g", ds1);
__asm__("lda ($fc),y");
__asm__("sta ($fe),y");
__asm__("dey");
__asm__("jmp %g", dl1);
ds1:
__asm__("dec $fc"); // LSB of src
__asm__("lda $fe"); // LSB of dst
__asm__("bne %g", ds2);
__asm__("dec $ff"); // MSB of dst
__asm__("ldx #$00");
dl2:
__asm__("cpx $fb"); // MSB of n
__asm__("beq %g", ds2); // No more complete 256 byte blocks, done!
__asm__("dec $fd"); // MSB of source
__asm__("dec $ff"); // MSB of dest
__asm__("ldy #$00"); // Copy one block of 256 bytes
dl3:
__asm__("dey");
__asm__("lda ($fc),y");
__asm__("sta ($fe),y");
__asm__("cpy #$00");
__asm__("bne %g", dl3);
__asm__("inx");
__asm__("jmp %g", dl2);
ds2:
__asm__("dec $fe"); // LSB of dst
__asm__("lda $fa"); // LSB of n
__asm__("bne %g", ds3);
__asm__("dec $fb"); // MSB of n
ds3:
__asm__("dec $fa"); // LSB of n
__asm__("bne %g", dl1); // Loop
__asm__("lda $fb"); // MSB of n
__asm__("bne %g", dl1); // Loop
#ifdef AUXMEM
__asm__("sta $c002"); // Read main mem
__asm__("sta $c004"); // Write main mem