From 55a418e65d9d5769482195e41330995e2206908a Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Fri, 16 Jan 2015 23:02:22 +0000
Subject: [PATCH] tgl6502: Get the romdisc fixed and as far as entering
 userspace

---
 Kernel/platform-tgl6502/devrd.c   | 29 ++++++++-----
 Kernel/platform-tgl6502/tgl6502.s | 72 +++++++++++++++++++++++++------
 2 files changed, 79 insertions(+), 22 deletions(-)

diff --git a/Kernel/platform-tgl6502/devrd.c b/Kernel/platform-tgl6502/devrd.c
index 0361428d..8766edef 100644
--- a/Kernel/platform-tgl6502/devrd.c
+++ b/Kernel/platform-tgl6502/devrd.c
@@ -7,6 +7,13 @@
 #include <printf.h>
 #include <devrd.h>
 
+uint16_t romd_roff;
+uint8_t romd_rmap;
+uint8_t romd_bank;
+
+extern void __fastcall__ rd_copyin(uint16_t addr);
+
+
 static int rd_transfer(bool is_read, uint8_t rawflag)
 {
     blkno_t block;
@@ -16,15 +23,12 @@ static int rd_transfer(bool is_read, uint8_t rawflag)
     int ct = 0;
     int map;
     irqflags_t irq;
-    uint8_t old;
-    uint16_t romd_roff;
-    uint8_t romd_rmap;
 
     /* RAW won't work yet this is just an initial hack */
     if(rawflag) {
         dlen = udata.u_count;
         dptr = (uint16_t)udata.u_base;
-        if (dptr & 0x1FF) {
+        if (dptr & 0x1FF || 1 /* BROKEN */) {
             udata.u_error = EIO;
             return -1;
         }
@@ -44,13 +48,18 @@ static int rd_transfer(bool is_read, uint8_t rawflag)
         romd_roff = (block << 9);
         /* 8K block we need to select */
         romd_rmap = 0x48 + (block >> 4);
-        /* Hack for now for testing */
+        /* Map it over a page we are not copying into */
+        if (dptr >= 0xC000) {
+            romd_roff += 0xA000;
+            romd_bank = 0;
+        } else {
+            romd_roff += 0xC000;
+            romd_bank = 1;
+        }
         irq = di();
-        old = *(uint8_t *)0xFF91;
-        *(uint8_t *)0xFF91 = romd_rmap;
-        if (is_read)
-            memcpy((void *)dptr, (void *)(0xE000 + romd_roff), 512);
-        *(uint8_t *)0xFF91 = old;
+        if (is_read) {
+            rd_copyin(dptr);
+        }
         irqrestore(irq);
         block++;
         ct++;
diff --git a/Kernel/platform-tgl6502/tgl6502.s b/Kernel/platform-tgl6502/tgl6502.s
index 688002c5..63cee77c 100644
--- a/Kernel/platform-tgl6502/tgl6502.s
+++ b/Kernel/platform-tgl6502/tgl6502.s
@@ -35,9 +35,9 @@
 	    .import _unix_syscall
 	    .import _platform_interrupt
 	    .import _kernel_flag
-	    .import copycommon
 
-	    .import incaxy		; from the C runtime
+	    .import outcharhex
+	    .import outxa
 
             .include "kernel.def"
             .include "../kernel02.def"
@@ -119,7 +119,6 @@ _program_vectors:
 	    ; will exit with interrupts off
 	    sei
 	    ;
-	    jsr copycommon
 	    ; our C caller will invoke us with the pointer in x,a
 	    ; just pass it on
 	    jsr map_process
@@ -170,6 +169,9 @@ program_vectors_k:
 ;	save/restore are used so that the kernel can play with its internal
 ;	banking/mappings without having to leave interrupts off all the time
 ;
+;	ptr1 and tmp1 may be destroyed by these methods, but no other
+;	temporaries.
+;
 map_process_always:
 	    pha
 	    txa
@@ -290,12 +292,6 @@ saved_map:  .byte 0
 ; corrupting other registers
 
 outchar:
-	    pha
-outcharw:
-	    lda $FF01
-	    and #4
-	    beq outcharw
-	    pla
 	    sta $FF03
 	    rts
 
@@ -371,7 +367,7 @@ syscall_entry:
 	    ; to the user stack we'll have finished with them
 	    lda sp
 	    ldx sp+1
-	    jsr incaxy
+	    jsr cincaxy
 	    sta sp
 	    stx sp+1
 
@@ -471,13 +467,19 @@ platform_doexec:
 ;
 	    stx ptr1+1
 	    sta ptr1
+
+	    ldy #'E'
+	    sty $FF03
+	    jsr outxa
 ;
 ;	Set up the C stack
 ;
 	    lda U_DATA__U_ISP
 	    sta sp
-	    lda U_DATA__U_ISP+1
-            sta sp+1
+	    ldx U_DATA__U_ISP+1
+            stx sp+1
+
+	    jsr outxa
 ;
 ;	Set up the 6502 stack
 ;
@@ -493,3 +495,49 @@ _unix_syscall_i:
 _platform_interrupt_i:
 	    jmp _platform_interrupt
 
+
+;
+;	Hack for common runtime helper (fixme move helpers to common)
+;
+cincaxy:sty tmp1
+	clc
+	adc tmp1
+	bcc incaxy2
+	inx
+incaxy2:rts
+
+;
+;	ROM disc copier (needs to be in common), call with ints off
+;
+;	AX = ptr, length always 512, src and page in globals
+;
+
+	.import _romd_bank, _romd_roff, _romd_rmap;
+	.export _rd_copyin
+
+_rd_copyin:
+	sta ptr1
+	stx ptr1+1		; Save the target
+	ldy _romd_bank		; 0 = A0, 1 = C0, pick based on target
+	lda $FF8F,y		;
+	pha
+	lda _romd_rmap
+	sta $FF8F,y
+	lda _romd_roff
+	sta ptr2
+	lda _romd_roff+1
+	sta ptr2+1
+	ldy #0
+	ldx #2
+rd_cl:	lda (ptr2),y
+	sta (ptr1),y
+	iny
+	bne rd_cl
+	inc ptr1+1
+	inc ptr2+1
+	dex
+	bne rd_cl
+	pla
+	ldy _romd_bank
+	sta $FF8F,y
+	rts
-- 
2.34.1