From ccf1ea4a34a789da326a321589c2757e5b1d749c Mon Sep 17 00:00:00 2001 From: "Juan J. Martinez" Date: Thu, 18 May 2023 12:18:24 +0100 Subject: Formatting, project page --- README.md | 124 +++++++++++++++++++++++++++++++------------------------------- 1 file changed, 63 insertions(+), 61 deletions(-) (limited to 'README.md') diff --git a/README.md b/README.md index 16f2bad..f555daf 100644 --- a/README.md +++ b/README.md @@ -284,29 +284,29 @@ branching instructions: #### Assembler directives -.org addr +**.org addr** Set the address to that value. By default the starting address is `0x0000`. -.db imm [, imm] +**.db imm [, imm]** Literal byte. Label can be used with `<` prefix for the low byte of the address and `>`for the high byte. -.dw imm [, imm] +**.dw imm [, imm]** Literal word (16-bit value). -.ds count, imm +**.ds count, imm** Generates `count` bytes with value `imm`. -.equ id value +**.equ id value** Define an ID assigning a constant value. When the id is used, it will be replaced with its value. -.include "filename" +**.include "filename"** Assemble the file at current position. -.incbin "filename" +**.incbin "filename"** Read the file and add the content to the output at current position. -.incpng "filename" +**.incpng "filename"** Read the PNG image and add the content to the output at current position. The image colors will be matched with the TR8 palette and any non-matching color will be condiered transparent and the index `128` will be used. @@ -315,218 +315,218 @@ The blitter won't draw any pixel with index larger than 15. #### Load and Store -LD r1, r2 +**LD r1, r2** Load the value of r2 in r1. -LD r1, imm +**LD r1, imm** Load the immediate value in r1. -LD [r1:r2], r3 +**LD [r1:r2], r3** Load the value of r3 in the memory address provided by r1:r2. -LD r3, [r1:r2] +**LD r3, [r1:r2]** Load into r3 the value in the memory address provided by r1:r2. -LD [SP + imm], r1 +**LD [SP + imm], r1** Load r1 into the stack on top address plus the immediate value. -LD r1, [SP + imm] +**LD r1, [SP + imm]** Load into r1 the stack value on top address plus the immediate value. #### Stack -PUSH r1 +**PUSH r1** Save the value of r1 on the top of the stack. -POP r1 +**POP r1** Restore the value of r1 by popping it from the top of the stack. -PUSH F +**PUSH F** Save the flags in the stack. -POP F +**POP F** Restore the flags from the top of the stack. -XSP r1 +**XSP r1** Exchange the high byte of the stack pointer by the value in r1. #### Logical -AND r1, r2 +**AND r1, r2** Logical AND between r1 and r2, storing the result in r1. Affected flags: ZF, SF -AND r1, imm +**AND r1, imm** Logical AND between r1 and immediate value, storing the result in r1. Affected flags: ZF, SF -OR r1, r2 +**OR r1, r2** Logical OR between r1 and r2, storing the result in r1. Affected flags: ZF, SF -OR r1, imm +**OR r1, imm** Logical OR between r1 and immediate value, storing the result in r1. Affected flags: ZF, SF -XOR r1, r2 +**XOR r1, r2** Logical exclusive OR between r1 and r2, storing the result in r1. Affected flags: ZF, SF -XOR r1, imm +**XOR r1, imm** Logical exclusive OR between r1 and immediate value, storing the result in r1. Affected flags: ZF, SF #### Arithmetic -INC r1 +**INC r1** Incremet r1. Affected flags: ZF, CF, OF, SF -DEC r1 +**DEC r1** Decrement r1. Affected flags: ZF, CF, OF, SF -ADD r1, r2 +**ADD r1, r2** Add r1 and r2, storing the result in r1. Affected flags: ZF, CF, OF, SF -ADD r1, imm +**ADD r1, imm** Add r1 and the immediate value, storing the result in r1. Affected flags: ZF, CF, OF, SF -SUB r1, r2 +**SUB r1, r2** Subtract r2 to r1, storing the result in r1. Affected flags: ZF, CF, OF, SF -SUB r1, imm +**SUB r1, imm** Subtract the immediate value to r1, storing the result in r1. Affected flags: ZF, CF, OF, SF -CMP r1, r2 +**CMP r1, r2** 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 +**CMP r1, imm** 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 -SHL r1, n +**SHL r1, n** Shift r1 n bits to the left (0 to 7), storing the result in r1. Affected flags: ZF, CF, SF -SHR r1, n +**SHR r1, n** Shift r1 n bits to the right (0 to 7), storing the result in r1. Affected flags: ZF, CF, SF -ROL r1, n +**ROL r1, n** Rotate r1 n bits to the left (0 to 7), storing the result in r1. Affected flags: ZF, CF, SF -ROR r1, n +**ROR r1, n** Rotate r1 n bits to the right (0 to 7), storing the result in r1. Affected flags: ZF, CF, SF -BIT r1, n +**BIT r1, n** Test bit n (0 to 7) or r1, setting ZF if it is set or clearing it otherwise. Affected flags: ZF #### Jump and Call -JMP addr +**JMP addr** Set the PC to the 16-bit address. -CALL addr +**CALL addr** Store the next PC in the stack (16-bit address) and sets the PC to the 16-bit address. -CALL [r1:r2] +**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. -RET +**RET** Return from a call by setting PC to the top 16-bit value popped from the stack. #### Branching -BZ inst +**BZ inst** Branch if Zero, will run the next instruction if ZF is set. Affected flags: BF -BNZ inst +**BNZ inst** Branch if not Zero, will run the next instruction if ZF flag is not set. Affected flags: BF -BC inst +**BC inst** Branch if Carry, will run the next instruction if CF flag is set. Affected flags: BF -BNC inst +**BNC inst** Branch if not Carry, will run the next instruction if CF flag is not set. Affected flags: BF -BO inst +**BO inst** Branch if Overflow, will run the next instruction if OF flag is set. Affected flags: BF -BNO inst +**BNO inst** Branch if not Overflow, will run the next instruction if OF flag is not set. Affected flags: BF -BS inst +**BS inst** Branch if Sign, will run the next instruction if SF flag is set. Affected flags: BF -BNS inst +**BNS inst** Branch if not Sign, will run the next instruction if SF flag is set. Affected flags: BF -BI inst +**BI inst** Branch if Interrupt, will run the next instruction if IF flag is set. Affected flags: BF -BNI inst +**BNI inst** Branch if not Interrupt, will run the next instruction if IF flag is not set. Affected flags: BF #### IO, flags and Misc -HALT +**HALT** Stop the execution until there is frame interrupt. If the interruption flag is set, this will hang the CPU. -PORT r1, r2 +**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. -NOP +**NOP** No instruction has no effect. -SIF +**SIF** Set IF, disabling the interrupt. Affected flags: IF -CIF +**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. Affected flags: IF -CCF +**CCF** Clear carry flag. Affected flags: CF -SCF +**SCF** Set carry flag. Affected flags: CF -COF +**COF** Clear overflow flag. Affected flags: OF -IRET +**IRET** Return from an interrupt handler by restoring F and PC from the stack. Affected flags: IF @@ -546,3 +546,5 @@ This was made by [Juan J. Martinez](https://www.usebox.net/jjm/about/me/). The code is MIT licensed. +Project website: https://git.usebox.net/tr8vm/about/ + -- cgit v1.2.3