1 /*****************************************************************************/
5 /* 65C02 specific optimizations */
9 /* (C) 2001 Ullrich von Bassewitz */
11 /* D-70597 Stuttgart */
12 /* EMail: uz@cc65.org */
15 /* This software is provided 'as-is', without any expressed or implied */
16 /* warranty. In no event will the authors be held liable for any damages */
17 /* arising from the use of this software. */
19 /* Permission is granted to anyone to use this software for any purpose, */
20 /* including commercial applications, and to alter it and redistribute it */
21 /* freely, subject to the following restrictions: */
23 /* 1. The origin of this software must not be misrepresented; you must not */
24 /* claim that you wrote the original software. If you use this software */
25 /* in a product, an acknowledgment in the product documentation would be */
26 /* appreciated but is not required. */
27 /* 2. Altered source versions must be plainly marked as such, and must not */
28 /* be misrepresented as being the original software. */
29 /* 3. This notice may not be removed or altered from any source */
32 /*****************************************************************************/
46 /*****************************************************************************/
48 /*****************************************************************************/
52 /*****************************************************************************/
53 /* Helper functions */
54 /*****************************************************************************/
58 /*****************************************************************************/
60 /*****************************************************************************/
64 unsigned Opt65C02Ind (CodeSeg* S)
65 /* Try to use the indirect addressing mode where possible */
70 /* Generate register info for this step */
73 /* Walk over the entries */
75 while (I < CS_GetEntryCount (S)) {
78 CodeEntry* E = CS_GetEntry (S, I);
80 /* Check for addressing mode indirect indexed Y where Y is zero.
81 * Note: All opcodes that are available as (zp),y are also available
82 * as (zp), so we can ignore the actual opcode here.
84 if (E->AM == AM65_ZP_INDY && E->RI->In.RegY == 0) {
86 /* Replace it by indirect addressing mode */
87 CodeEntry* X = NewCodeEntry (E->OPC, AM65_ZP_IND, E->Arg, 0, E->LI);
88 CS_InsertEntry (S, X, I+1);
101 /* Free register info */
104 /* Return the number of changes made */