new c lib (+sms): incorporate devkitSMS into z88dk

[z88dk]

new c lib (+sms): incorporate devkitSMS into z88dk

[aralbrec]

I've finished incorporating the kit into z88dk but it still needs testing. I have not done anything about GG or SC1000 targeting because I'm not sure yet if these machine variations are better served by an independent target.

The kit is configured by editing z88dk/libsrc/_DEVELOPMENT/target/sms/config_devkitSMS.m4 and then re-building the sms library by running "Winmake sms" or "make TARGET=sms" from z88dk/libsrc/_DEVELOPMENT

The kit is compatible with any crt but there is a special one selectable from the compile line with "startup=8" that places the kit's two restarts at 0x08 and 0x18. If this crt is used, the config variables "__SMSLIB_ISRST_SMSCRT0RST08" and "__SMSLIB_ISRST_SMSCRT0RST18" should be set non-zero so that C calls will be routed through the restarts. Other crts must have these set to zero so that calls are made instead of rst.

Differences from devkitSMS itself:

• all functions are written in assembly language
• functions are partitioned into individual source files so that they can be linked individually
• the macros used to specify the binary headers are made inert as z88dk specifies header data via pragmas
• the devkitSMS tools number memory banks in decimal; at this time z88dk is following sega's tech doc and is numbering banks in hexadecimal.

devkitSMS also has a few tools associated with it to help create .sms files from sdcc's minimal output. z88dk is able to create sms files directly from the compile line so these are not necessary. One tool that might nevertheless be useful is "assets2banks" that will try to distribute data to different memory banks compactly. In z88dk it's very easy to manually assign code and data to banks but there is no automatic assignment like this tool performs.

I will be committing some examples in the course of testing.

Typical compile lines:

sccz80:
zcc +sms -vn -startup=8 -clib=new -O3 test.c -o test -create-app -pragma-include:zpragma.inc

sdcc:
zcc +sms -vn -startup=8 -clib=sdcc_iy -SO3 --max-allocs-per-node200000 test.c -o test -create-app -pragma-include:zpragma.inc

where zpragma.inc contains pragmas defining various options. An example here:

// Standard SMS Header

#pragma output   SMS_HDR_PRODUCT_CODE = 107026
#pragma output   SMS_HDR_VERSION      = 1
#pragma output   SMS_HDR_REGION       = 0x3
#pragma output   SMS_HDR_ROM_SIZE     = 0x1              // ignored; rom size is always set to 32k

// SDSC Header - not generated if no SDSC pragmas are present

#pragma output   SDSC_HDR_VERSION     = 1046
#pragma output   SDSC_HDR_DATE        = 20160131         // if omitted current date is used
#pragma redirect SDSC_HDR_AUTHOR      = _author
#pragma redirect SDSC_HDR_NAME        = _name
#pragma redirect SDSC_HDR_DESCRIPTION = _description

// Change ORG Address of Banks - the default for all banks is 0x8000
// You would not normally change anything; this is an example only

#pragma output   CRT_ORG_BANK_05      = 0x4000           // BANKS are defined from 02 through 1F in hex

In the SDSC header above, "author", "name" and "description" must be const character strings defined in the program.

[aralbrec]

Move the bugfixing activity to #145