From 5c38e5f05abb9b821b5cbfe291993f9989b339c0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rados=C5=82aw=20Kujawa?= <radoslaw.kujawa@c0ff33.net>
Date: Mon, 23 Jan 2017 14:38:50 +0100
Subject: [PATCH] Add emulation of LDX, TXA, TYA, TXS, TAX, TAY, TSX.

---
 src/65c02isa.csv | 22 ++++++++--------
 src/emulation.c  | 67 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 78 insertions(+), 11 deletions(-)

diff --git a/src/65c02isa.csv b/src/65c02isa.csv
index 86053d1..b036351 100644
--- a/src/65c02isa.csv
+++ b/src/65c02isa.csv
@@ -137,7 +137,7 @@ OP_STX_ZP,"stx",ZP,2,NULL
 OP_SMB0_ZP,"smb0",ZP,2,NULL
 OP_DEY,"dey",IMPLIED,1,emul_dey
 OP_BIT_IMM,"bit",IMMEDIATE,2,NULL
-OP_TXA,"txa",IMPLIED,1,NULL
+OP_TXA,"txa",IMPLIED,1,emul_txa
 OP_NOPI_8C,"nop",IMPLIED,1,NULL
 OP_STY_ABS,"sty",ABSOLUTE,3,NULL
 OP_STA_ABS,"sta",ABSOLUTE,3,NULL
@@ -151,9 +151,9 @@ OP_STY_ZPX,"sty",ZPX,2,NULL
 OP_STA_ZPX,"sta",ZPX,2,NULL
 OP_STX_ZPY,"stx",ZPY,2,NULL
 OP_SMB1_ZP,"smb1",ZP,2,NULL
-OP_TYA,"tya",IMPLIED,1,NULL
+OP_TYA,"tya",IMPLIED,1,emul_tya
 OP_STA_ABSY,"sta",ABSOLUTEY,3,NULL
-OP_TXS,"txs",IMPLIED,1,NULL
+OP_TXS,"txs",IMPLIED,1,emul_txs
 OP_NOPI_9C,"nop",IMPLIED,1,NULL
 OP_STZ_ABS,"stz",ABSOLUTE,3,emul_stz
 OP_STA_ABSX,"sta",ABSOLUTEX,3,NULL
@@ -161,19 +161,19 @@ OP_STZ_ABSX,"stz",ABSOLUTEX,3,emul_stz
 OP_BBS1_REL,"bbs1",ZPR,2,NULL
 OP_LDY_IMM,"ldy",IMMEDIATE,2,NULL
 OP_LDA_IZPX,"lda",IZPX,2,emul_lda
-OP_LDX_IMM,"ldx",IMMEDIATE,2,NULL
+OP_LDX_IMM,"ldx",IMMEDIATE,2,emul_ldx
 OP_NOPI_A4,"nop",IMPLIED,1,NULL
 OP_LDY_ZP,"ldy",ZP,2,NULL
 OP_LDA_ZP,"lda",ZP,2,emul_lda
-OP_LDX_ZP,"ldx",ZP,2,NULL
+OP_LDX_ZP,"ldx",ZP,2,emul_ldx
 OP_SMB2_ZP,"smb2",ZP,2,NULL
-OP_TAY,"tay",IMPLIED,1,NULL
+OP_TAY,"tay",IMPLIED,1,emul_tay
 OP_LDA_IMM,"lda",IMMEDIATE,2,emul_lda
-OP_TAX,"tax",IMPLIED,1,NULL
+OP_TAX,"tax",IMPLIED,1,emul_tax
 OP_NOPI_AC,"nop",IMPLIED,1,NULL
 OP_LDY_ABS,"ldy",ABSOLUTE,3,NULL
 OP_LDA_ABS,"lda",ABSOLUTE,3,emul_lda
-OP_LDX_ABS,"ldx",ABSOLUTE,3,NULL
+OP_LDX_ABS,"ldx",ABSOLUTE,3,emul_ldx
 OP_BBS2_REL,"bbs2",ZPR,2,NULL
 OP_BCS_REL,"bcs",RELATIVE,2,NULL
 OP_LDA_IZPY,"lda",IZPY,2,emul_lda
@@ -181,15 +181,15 @@ OP_LDA_IZP,"lda",IZP,2,emul_lda
 OP_NOPI_B4,"nop",IMPLIED,1,NULL
 OP_LDY_ZPX,"ldy",ZPX,2,NULL
 OP_LDA_ZPX,"lda",ZPX,2,emul_lda
-OP_LDX_ZPY,"ldx",ZPY,1,NULL
+OP_LDX_ZPY,"ldx",ZPY,1,emul_ldx
 OP_SMB3_ZP,"smb3",ZP,2,NULL
 OP_CLV,"clv",IMPLIED,1,NULL
 OP_LDA_ABSY,"lda",ABSOLUTEY,3,emul_lda
-OP_TSX,"tsx",IMPLIED,1,NULL
+OP_TSX,"tsx",IMPLIED,1,emul_tsx
 OP_NOPI_BC,"nop",IMPLIED,1,NULL
 OP_LDY_ABSX,"ldy",ABSOLUTEX,3,NULL
 OP_LDA_ABSX,"lda",ABSOLUTEX,3,emul_lda
-OP_LDX_ABSY,"ldx",ABSOLUTEY,3,NULL
+OP_LDX_ABSY,"ldx",ABSOLUTEY,3,emul_ldx
 OP_BBS3_REL,"bbs3",ZPR,2,NULL
 OP_CPY_IMM,"cpy",IMMEDIATE,2,NULL
 OP_CMP_IZPX,"cmp",IZPX,2,NULL
diff --git a/src/emulation.c b/src/emulation.c
index 4ff5e41..dd9637a 100644
--- a/src/emulation.c
+++ b/src/emulation.c
@@ -72,6 +72,16 @@ emul_lda(rk65c02emu_t *e, void *id, instruction_t *i)
 	instruction_status_adjust_negative(e, e->regs.A);
 }
 
+/* LDX - load to X */
+void
+emul_ldx(rk65c02emu_t *e, void *id, instruction_t *i)
+{
+	e->regs.X = instruction_data_read_1(e, (instrdef_t *) id, i);
+
+	instruction_status_adjust_zero(e, e->regs.X);
+	instruction_status_adjust_negative(e, e->regs.X);
+}
+
 /* NOP - do nothing */
 void
 emul_nop(rk65c02emu_t *e, void *id, instruction_t *i)
@@ -130,3 +140,60 @@ emul_stz(rk65c02emu_t *e, void *id, instruction_t *i)
 	instruction_data_write_1(e, id, i, 0);
 }
 
+/* TAX - transfer accumulator to X */
+void
+emul_tax(rk65c02emu_t *e, void *id, instruction_t *i)
+{
+	e->regs.X = e->regs.A;
+
+	instruction_status_adjust_zero(e, e->regs.X);
+	instruction_status_adjust_negative(e, e->regs.X);
+}
+
+/* TAY - transfer accumulator to Y */
+void
+emul_tay(rk65c02emu_t *e, void *id, instruction_t *i)
+{
+	e->regs.Y = e->regs.A;
+
+	instruction_status_adjust_zero(e, e->regs.Y);
+	instruction_status_adjust_negative(e, e->regs.Y);
+}
+
+/* TSX - transfer stack pointer to X */
+void
+emul_tsx(rk65c02emu_t *e, void *id, instruction_t *i)
+{
+	e->regs.X = e->regs.SP;
+
+	instruction_status_adjust_zero(e, e->regs.X);
+	instruction_status_adjust_negative(e, e->regs.X);
+}
+
+/* TXA - transfer X to accumulator */
+void
+emul_txa(rk65c02emu_t *e, void *id, instruction_t *i)
+{
+	e->regs.A = e->regs.X;
+
+	instruction_status_adjust_zero(e, e->regs.A);
+	instruction_status_adjust_negative(e, e->regs.A);
+}
+
+/* TXS - transfer X to stack pointer */
+void
+emul_txs(rk65c02emu_t *e, void *id, instruction_t *i)
+{
+	e->regs.SP = e->regs.X;
+}
+
+/* TYA - transfer Y to accumulator */
+void
+emul_tya(rk65c02emu_t *e, void *id, instruction_t *i)
+{
+	e->regs.A = e->regs.Y;
+
+	instruction_status_adjust_zero(e, e->regs.A);
+	instruction_status_adjust_negative(e, e->regs.A);
+}
+