From 4fd47c85d2419ac8fa788696f7fda03cf3ce8124 Mon Sep 17 00:00:00 2001
From: Joshua Wise <joshua@nyus.joshuawise.com>
Date: Sat, 19 Apr 2008 05:07:51 -0400
Subject: [PATCH] Add ld (bc/de),a, ld a,(bc/de)

---
 GBZ80Core.v     |  1 +
 Makefile        |  3 ++-
 allinsns.v      |  1 +
 diag.asm        |  6 +-----
 insn_ldbcde_a.v | 26 ++++++++++++++++++++++++++
 5 files changed, 31 insertions(+), 6 deletions(-)
 create mode 100644 insn_ldbcde_a.v

diff --git a/GBZ80Core.v b/GBZ80Core.v
index 73785c5..3931bdd 100644
--- a/GBZ80Core.v
+++ b/GBZ80Core.v
@@ -73,6 +73,7 @@
 `define INSN_INCDEC_reg8	8'b00xxx10x
 `define INSN_LD8M_A		8'b111x0000	// 1111 for ld A, x; 1110 for ld x, A; bit 1 specifies 16m8 or 8m8
 `define INSN_LD16M_A		8'b111x1010	// 1111 for ld A, x; 1110 for ld x, A; bit 1 specifies 16m8 or 8m8
+`define INSN_LDBCDE_A		8'b000xx010	// 0000 for BC, 0001 for DE, 1010 for A,(x), 0010 for (x),A
 
 `define INSN_cc_NZ		2'b00
 `define INSN_cc_Z		2'b01
diff --git a/Makefile b/Makefile
index 0aaf564..cf89f73 100644
--- a/Makefile
+++ b/Makefile
@@ -5,7 +5,8 @@ VLOGS = 7seg.v GBZ80Core.v insn_call-callcc.v insn_incdec16.v \
 	insn_ld_sp_hl.v insn_pop_reg.v insn_rst.v System.v CPUDCM.v \
 	insn_alu_a.v insn_halt.v insn_jp-jpcc.v insn_ld_hl_reg.v \
 	insn_ld_reg_imm8.v insn_ldx_ahl.v insn_push_reg.v insn_vop_intr.v \
-	Timer.v LCDC.v insn_ldm8_a.v insn_ldm16_a.v Framebuffer.v
+	Timer.v LCDC.v insn_ldm8_a.v insn_ldm16_a.v Framebuffer.v \
+	insn_ldbcde_a.v
 
 all: CoreTop_rom.svf CoreTop_diag.svf CoreTop.twr
 
diff --git a/allinsns.v b/allinsns.v
index 8d33aa2..0a62af3 100644
--- a/allinsns.v
+++ b/allinsns.v
@@ -25,3 +25,4 @@
 `include "insn_incdec_reg8.v"
 `include "insn_ldm8_a.v"
 `include "insn_ldm16_a.v"
+`include "insn_ldbcde_a.v"
\ No newline at end of file
diff --git a/diag.asm b/diag.asm
index e7bb0d4..e9a9f19 100644
--- a/diag.asm
+++ b/diag.asm
@@ -94,12 +94,8 @@ putscreen:
 	ld hl, $8000	; Copy two tiles.
 	ld de, tiles
 	ld c, $20
-.cloop:	push hl
-	ld h, d
-	ld l, e
-	ld a, [hl]
+.cloop:	ld a, [de]
 	inc de
-	pop hl
 	ld [hli], a
 	ld [hli], a
 	dec c
diff --git a/insn_ldbcde_a.v b/insn_ldbcde_a.v
new file mode 100644
index 0000000..2a91dc6
--- /dev/null
+++ b/insn_ldbcde_a.v
@@ -0,0 +1,26 @@
+`ifdef EXECUTE
+	`INSN_LDBCDE_A: begin
+		case (cycle)
+		0:	if (opcode[3]) begin
+				if (opcode[4]) begin `EXEC_READ(`_DE) end
+				else begin `EXEC_READ(`_BC) end
+			end else begin
+				if (opcode[4]) begin `EXEC_WRITE(`_DE, `_A) end
+				else begin `EXEC_WRITE(`_BC, `_A) end
+			end
+		1:	begin
+				`EXEC_INC_PC
+				`EXEC_NEWCYCLE
+			end
+		endcase
+	end
+`endif
+
+`ifdef WRITEBACK
+	`INSN_LDBCDE_A: begin
+		case (cycle)
+		0:	begin end
+		1:	if (opcode[3]) `_A <= rdata;
+		endcase
+	end
+`endif
-- 
2.43.0