From 1c56880aecf83fac3f1a9f16d296c39573a65918 Mon Sep 17 00:00:00 2001 From: "Juan J. Martinez" Date: Mon, 1 May 2023 14:10:14 +0100 Subject: Typos, formatting --- README.md | 47 ++++++++++++++++++++++++++++++----------------- 1 file changed, 30 insertions(+), 17 deletions(-) diff --git a/README.md b/README.md index b39634b..f01719f 100644 --- a/README.md +++ b/README.md @@ -15,10 +15,10 @@ Sound: TBD Other features: -* programable in ASM +* programmable in ASM * TR-8 CPU - 16-bit registers: stack pointer (SP) and program counter (PC) - - 8-bit registers: 4 general purpose registers (a, b, x, y), flags refister (F) + - 8-bit registers: 4 general purpose registers (a, b, x, y), flags register (F) * frame interrupt (60Hz) and external IO interrupt * port based IO @@ -46,7 +46,7 @@ On Linux install a C compiler and the development packages for the requirements. Example on Debian/Ubuntu using `sudo`: - sudo apt install build-essential libsdl2-dev libsdl2-image-dev libsdl2-mixer-dev + sudo apt install build-essential libsdl2-dev libsdl2-mixer-dev Then run `make`. @@ -71,7 +71,8 @@ You can then compile and run the example with `make example`. The controller support d-pad with 4 directions, 2 action buttons, select and start. -Read the port `0xf0` for the 8 1-bit flags reporting the state of the controller 1, and `0xf1` for controller 2. +Read the port `0xf0` for the 8 1-bit flags reporting the state of the +controller 1, and `0xf1` for controller 2. ``` 76543210 @@ -87,7 +88,8 @@ Read the port `0xf0` for the 8 1-bit flags reporting the state of the controller ### Palette -Ports from `0xe0` to `0xef` can be used to select the colors to use in the 16 color palette from the 32 available. +Ports from `0xe0` to `0xef` can be used to select the colors to use in the 16 +color palette from the 32 available. TODO: palette colours @@ -132,7 +134,7 @@ fill_loop: inc x bno jmp fill_loop - ; x overfows, so we increment a + ; x overflows, so we increment a ; and decrement y (one 256 block done) inc a dec y @@ -158,7 +160,8 @@ instructions: Set the address to that value. By default the starting address is `0x0000`. .db imm [, imm] -Literal byte. Label can be used with `<` prefix for the low byte of the address and `>`for the high byte. +Literal byte. Label can be used with `<` prefix for the low byte of the address +and `>`for the high byte. .dw imm [, imm] Literal word. @@ -253,11 +256,13 @@ Subtract the immediate value to r1, storing the result in r1. Affected flags: ZF, CF, OF, SF CMP r1, r2 -Perform a SUB of r1 minus r2, without storing the result and only updating the flags. +Perform a SUB of r1 minus r2, without storing the result and only updating the +flags. Affected flags: ZF, CF, OF, SF CMP r1, imm -Perform a SUB of r1 minus the immediate value without storing the result and only updating the flags. +Perform a SUB of r1 minus the immediate value without storing the result and +only updating the flags. Affected flags: ZF, CF, OF, SF #### Bit Operations @@ -279,7 +284,7 @@ Rotate r1 n bits to the right (0 to 7), storing the result in r1. Affected flags: ZF, CF, SF BIT r1, n -Test bit n (0 to 7) or r1, setting ZF if it is set or clearing it otherwise. +Test bit n (0 to 7) or r1, setting ZF if it is set or clearing it otherwise. Affected flags: ZF #### Jump and Call @@ -288,10 +293,12 @@ JMP addr Set the PC to the 16-bit address. CALL addr -Store the next PC in the stack (16-bit address) and sets te PC to the 16-bit address. +Store the next PC in the stack (16-bit address) and sets the PC to the 16-bit +address. CALL [r1:r2] -Store the next PC in the stack (16-bit address) and sets te PC to the 16-bit address provided by r1:r2. +Store the next PC in the stack (16-bit address) and sets te PC to the 16-bit +address provided by r1:r2. RET Return from a call by setting PC to the top 16-bit value popped from the stack. @@ -341,10 +348,12 @@ Affected flags: BF #### IO, flags and Misc HALT -Stop the execution until there is frame interrupt. If the interruption flag is set, this will hang the CPU. +Stop the execution until there is frame interrupt. If the interruption flag is +set, this will hang the CPU. PORT r1, r2 -Write the value of r2 in the port number provided by r1. If there is an output, the value will be stored in r1. +Write the value of r2 in the port number provided by r1. If there is an output, +the value will be stored in r1. NOP No instruction has no effect. @@ -354,7 +363,8 @@ Set IF, disabling the interrupt. Affected flags: IF CIF -Clear IF, enabling the interrupt. If called in an interrupt handler, it won't have effect. Use IRET instead to return from the interrupt to unset IF. +Clear IF, enabling the interrupt. If called in an interrupt handler, it won't +have effect. Use IRET instead to return from the interrupt to unset IF. Affected flags: IF CCF @@ -370,14 +380,17 @@ Clear overflow flag. Affected flags: OF IRET -Return from an interupt handler by setting PC to the top 16-bit value popped from the stack. It enables interrupts by clearing the interrupt flag. +Return from an interrupt handler by setting PC to the top 16-bit value popped +from the stack. It enables interrupts by clearing the interrupt flag. Affected flags: IF ### TR8 file format It is a binary file to be run on the TR-8. -It doesn't have a header and it will be loaded at `0x0000` address. The execution will start on that address with interruptions disabled (interruption flag set). +It doesn't have a header and it will be loaded at `0x0000` address. The +execution will start on that address with interruptions disabled (interruption +flag set). See the memory map for further information. -- cgit v1.2.3