6502/COMMON
1
0
Fork 0
mirror of https://github.com/Russell-S-Harper/COMMON.git synced 2024-09-27 21:57:36 +00:00
Code Issues Projects Releases Wiki Activity

Cleaning up definitions, and preparing for multitasking.

Browse Source
This commit is contained in:
Russell-S-Harper 2018-10-04 21:03:55 -04:00
parent 65267903c1
commit c3b51fe912
2 changed files with 37 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
common/common.h
View File

@ -47,7 +47,7 @@
; CMR pq 0f pq F <- Rp <=> Rq - compare registers
; 40 bytes in page zero for common registers
_R0 = $b8
_R0 = $100 - 4 * (10 + 9)
_R1 = _R0 + 4
_R2 = _R1 + 4
_R3 = _R2 + 4
@ -58,15 +58,16 @@ _R7 = _R6 + 4
_R8 = _R7 + 4
_R9 = _R8 + 4
; 32 bytes in page zero for internal registers
_I0 = $e0 ; workspace
; 36 bytes in page zero for internal registers
_I0 = _R9 + 4 ; workspace
_I1 = _I0 + 4
_I2 = _I1 + 4
_I3 = _I2 + 4
_I4 = _I3 + 4
_I5 = _I4 + 4
_I6 = _I5 + 4 ; register I6 maintains common status
_I7 = _I6 + 4 ; register I7 saves/restores processor status
_I7 = _I6 + 4 ; register I7 maintains process information for context switching
_I8 = _I7 + 4 ; register I8 saves/restores processor status
; register I6 maintains common status
; (dd cc bb aa) aa: index for register stack RS / ccbb: program counter PC / dd: flags F UONPZLGE
@ -86,21 +87,33 @@ _F_N = 32 ; if Rr < 0.0 (after TST)
_F_O = 64 ; if overflow (after arithmetic operations)
_F_U = 128 ; if underflow (after arithmetic operations)
; register I7 saves/restores processor status
; register I7 maintains process information for context switching
_PST = _I7 ; current process status
_PSI = _PST + 1 ; process stack index to save/restore
_PD0 = _PSI + 1 ; two bytes for process
_PD1 = _PD0 + 1
; register I8 saves/restores processor status
; (dd cc bb aa) aa: accumulator, bb: index X, cc: index Y, dd: processor status
_ACC = _I7 ; saved accumulator to restore
_ACC = _I8 ; saved accumulator to restore
_IDX = _ACC + 1 ; saved index X to restore
_IDY = _IDX + 1 ; saved index Y to restore
_PS = _IDY + 1 ; saved processor status to restore
; 224 bytes of page two
; 6502 stack resides on page one
; using some of page two for register stack
_RS = $200 ; register stack
_RSS = (FN_FX - _RS) ; register stack size
_RSS = _R0 ; register stack size
; for context switching, at least _R0 to FN_FX-1 plus one byte for the stack pointer need to be saved and restored
; for context switching, _R0 to _RS + _RSS - 1 needs to be saved and restored
; this should comprise two pages or 512 bytes
; last 32 bytes of page two
FN_FX = $2e0 ; list of system and user functions
_PR = _RS + _RSS ; running processes
_PRS = FN_FX - _PR ; running process size
; 32 bytes of page two
FN_FX = $300 - 2 * 16 ; list of system and user functions
; function constants
_ESC_C = $00

22
emulator/main.c
View File

@ -2,11 +2,15 @@
#include <stdio.h>
#include "emulator.h"
/* Register E maintains common status */
#define _RE 0xf8
/* Register I6 maintains common status */
#define _R0 0xb4
#define _R8 0xd4
#define _I0 0xdc
#define _I6 0xf4
#define _I8 0xfc
/* (dd cc bb aa) aa: index for register stack RS / ccbb: program counter PC / dd: flags F UONPZLGE */
#define _RSI _RE /* register stack index */
#define _RSI _I6 /* register stack index */
#define _PCL _RSI + 1 /* program counter low */
#define _PCH _PCL + 1 /* program counter high */
#define _F _PCH + 1 /* flags */
@ -26,18 +30,18 @@ void hook() {
int i, j;
printf("\n%04x %u %u\n", pc, instructions, clockticks6502);
for (i = 0x00b8; i < 0x00d8; i += 4) {
printf("R%d: ", (i - 0x00b8) / 4);
for (i = _R0; i < _R8; i += 4) {
printf("R%d: ", (i - _R0) / 4);
for (j = 0; j < 4; ++j)
printf("%02x ", memory[i + j]);
if (((i - 0x00b8) / 4) % 4 == 3)
if (((i - _R0) / 4) % 4 == 3)
printf("\n");
}
for (i = 0x00e0; i < 0x0100; i += 4) {
printf("I%d: ", (i - 0x00e0) / 4);
for (i = _I0; i < _I8; i += 4) {
printf("I%d: ", (i - _I0) / 4);
for (j = 0; j < 4; ++j)
printf("%02x ", memory[i + j]);
if (((i - 0x00e0) / 4) % 4 == 3)
if (((i - _I0) / 4) % 4 == 3)
printf("\n");
}
}