From 02c08505eb0c93bc458c988079c0115e8ec78c8e Mon Sep 17 00:00:00 2001
From: Takashi Toyoshima <toyoshim@gmail.com>
Date: Tue, 9 Dec 2014 04:54:33 +0900
Subject: [PATCH] Implement I/O for lpc1114

Now Apple BASIC can run on the LPC1114 device :)
---
 6502.S   |   2 +
 Makefile |   4 +-
 apple2.S | 123 +++++++++++++++++++++++++++++++++++++++++++++++++++----
 reset.S  |   7 ++--
 uart.S   |  55 +++++++++++++++++++++++++
 5 files changed, 177 insertions(+), 14 deletions(-)

diff --git a/6502.S b/6502.S
index bdea756..7ac3caa 100644
--- a/6502.S
+++ b/6502.S
@@ -158,7 +158,9 @@
 .endm
 
 .macro _decode
+#ifdef DUMP
   bl   dump
+#endif
   mov  r0, PC
   _ldb
   lsls r1, r0, #2
diff --git a/Makefile b/Makefile
index 4ce3d88..a82646a 100644
--- a/Makefile
+++ b/Makefile
@@ -41,11 +41,11 @@ $(ROM).rom:
 
 # Test binary that runs on qemu user mode emulation for testing
 test: 6502.S test.c
-	$(CC) -mthumb -static $(FRAMEPTR) test.c 6502.S -o test && qemu-arm test 2> /dev/null
+	$(CC) -mthumb -static $(FRAMEPTR) -DDUMP test.c 6502.S -o test && qemu-arm test 2> /dev/null
 
 # Test binary that runs on qemu user mode emulation for functional tests
 ftest: 6502.S ftest.c
-	$(CC) -mthumb -static $(FRAMEPTR) ftest.c 6502.S -o ftest && qemu-arm ftest 2> flog
+	$(CC) -mthumb -static $(FRAMEPTR) -DDUMP ftest.c 6502.S -o ftest && qemu-arm ftest 2> flog
 
 # Assume a CQ Mary comaptible board.
 run: $(APP).bin
diff --git a/apple2.S b/apple2.S
index 3eaf8c9..fb218b9 100644
--- a/apple2.S
+++ b/apple2.S
@@ -5,6 +5,7 @@
   .thumb_func
 
   .extern basic_rom
+  .extern uart_putd
 
   .section .rodata
 dump0:
@@ -19,6 +20,8 @@ dump4:
   .ascii " SP=$\000"
 dump5:
   .ascii " NV-B_DIZC=\000"
+ascii:
+  .ascii "@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_ !\"#$%&'()*+,-./0123456789:;<=>?"
 
   .text
   .global cpu6502_dump
@@ -90,26 +93,128 @@ cpu6502_dump:
   .global cpu6502_load
   .type cpu6502_load, %function
 cpu6502_load:
-  movs r1, r0
+  movs r2, r0
   lsrs r0, #8
-  movs r2, #0xd0
-  cmps r0, r2
+  cmp  r0, #0xd0
   bhs  1f
-  // TODO: Load from RAM
-  movs r0, #0
+  cmp  r0, #0x04
+  blo  2f
+  cmp  r0, #0x08
+  blo  3f
+  cmp  r0, #0xc0
+  bhs  4f
+  // Load from Fake RAM (0x0800-0xbfff)
+  ldr  r0, =#ramfake
+  ldrb r0, [r0]
   mov  pc, lr
 1:
   // Load from ROM (0xd000-0xffff)
-  lsls r2, #8
-  subs r1, r1, r2
+  movs r0, #0xd0
+  lsls r0, #8
+  subs r2, r2, r0
   ldr  r0, =#basic_rom
-  adds r0, r0, r1
+  adds r0, r0, r2
   ldrb r0, [r0]
   mov  pc, lr
+2:
+  // Load from RAM (0x0000-0x03ff)
+  ldr  r0, =#ram0000
+  adds r0, r0, r2
+  ldrb r0, [r0]
+  mov  pc, lr
+3:
+  // Load from VRAM (0x0400-0x07ff)
+  movs r0, #0xff
+  mov  pc, lr
+4:
+  // Load from I/O (0xc000-0xcfff)
+  movs r0, #0
+  mov  pc, lr
 
   .global cpu6502_store
   .type cpu6502_store, %function
 cpu6502_store:
-  // TODO
+  movs r2, r0
+  lsrs r0, #8
+  cmp  r0, #0xd0
+  bhs  1f
+  cmp  r0, #0x04
+  blo  2f
+  cmp  r0, #0x08
+  blo  3f
+  cmp  r0, #0xc0
+  bhs  4f
+  // Store to Fake RAM (0x0800-0xbfff)
+  ldr  r0, =#ramfake
+  strb r1, [r0]
+  mov  pc, lr
+1:
+  // Store to ROM (0xd000-0xffff)
+  mov  pc, lr
+2:
+  // Store to RAM (0x0000-0x0400)
+  ldr  r0, =#ram0000
+  adds r0, r0, r2
+  strb r1, [r0]
+  mov  pc, lr
+3:
+  // Store to VRAM (0x0400-0x07ff)
+  cmp  r1, #0x7f
+  bne  1f
+  mov  pc, lr
+1:
+  push {lr}
+  push {r1-r2}
+  movs r0, #0x1b
+  bl   uart_putc
+  movs r0, #'['
+  bl   uart_putc
+  pop  {r1-r2}
+  movs r3, #0x04
+  lsls r3, r3, #8
+  subs r3, r2, r3
+  movs r2, r3
+  movs r0, #0x7f
+  ands r2, r2, r0
+  lsrs r3, r3, #7
+  cmp  r2, #0x50
+  blo  1f
+  subs r2, r2, #0x50
+  adds r3, r3, #0x10
+1:
+  cmp  r2, #0x28
+  blo  1f
+  subs r2, r2, #0x28
+  adds r3, r3, #0x08
+1:
+  mov  r0, r3
+  adds r0, r0, #1
+  push {r1-r2}
+  bl   uart_putd
+  movs r0, #';'
+  bl   uart_putc
+  pop  {r1-r2}
+  mov  r0, r2
+  adds r0, r0, #1
+  push {r1}
+  bl   uart_putd
+  movs r0, #'H'
+  bl   uart_putc
+  pop  {r1}
+  ldr  r2, =#ascii
+  movs r3, #0x3f
+  ands r3, r1, r3
+  adds r3, r3, r2
+  ldrb r0, [r3]
+  bl   uart_putc
+  pop  {pc}
+4:
+  // Load from I/O (0xc000-0xcfff)
+  movs r0, #0
   mov  pc, lr
 
+  .bss
+ram0000:
+  .skip 0x400
+ramfake:
+  .byte 0
diff --git a/reset.S b/reset.S
index a30551f..88a7ef1 100644
--- a/reset.S
+++ b/reset.S
@@ -22,9 +22,10 @@ _reset:
   ldr  r0, =#(_stack_top - 32)
   mov  sp, r0
   bl   uart_init
-  ldr  r0, =#hello
-  bl   uart_putstr
-
+  movs r0, #'>'
+  bl   uart_putc
+  //ldr  r0, =#hello
+  //bl   uart_putstr
   bl   cpu6502_reset
   bl   cpu6502_run
 1:
diff --git a/uart.S b/uart.S
index 0b73465..3b00b04 100644
--- a/uart.S
+++ b/uart.S
@@ -151,3 +151,58 @@ uart_puthex16:
   pop  {pc}
   .size uart_puthex16, .-uart_puthex16
 
+  // void uart_putd(char n);
+  .global uart_putd
+  .type uart_putd, %function
+uart_putd:
+  push {lr}
+  movs r1, #0
+  movs r2, #100
+  movs r3, #0
+1:
+  subs r0, r0, r2
+  bcc  1f
+  adds r1, r1, #1
+  b    1b
+1:
+  adds r0, r0, r2
+  cmp  r1, #0
+  beq  2f
+  push {r0}
+  mov  r0, r1
+  bl   uart_putx
+  pop  {r0}
+  movs r3, #1
+2:
+  movs r1, #0
+  movs r2, #10
+1:
+  subs r0, r0, r2
+  bcc  1f
+  adds r1, r1, #1
+  b    1b
+1:
+  adds r0, r0, r2
+  cmp  r1, #0
+  bne  1f
+  cmp  r3, #0
+  beq  2f
+1:
+  push {r0}
+  mov  r0, r1
+  bl   uart_putx
+  pop  {r0}
+  movs r3, #1
+2:
+  movs r1, #0
+  movs r2, #1
+1:
+  subs r0, r0, r2
+  bcc  1f
+  adds r1, r1, #1
+  b    1b
+1:
+  mov  r0, r1
+  bl   uart_putx
+  pop  {pc}
+